diff --git a/Userland/Services/Taskbar/CMakeLists.txt b/Userland/Services/Taskbar/CMakeLists.txt
index 3b0d10674e..14386c01fc 100644
--- a/Userland/Services/Taskbar/CMakeLists.txt
+++ b/Userland/Services/Taskbar/CMakeLists.txt
@@ -1,6 +1,7 @@
 set(SOURCES
     main.cpp
     ClockWidget.cpp
+    ShutdownDialog.cpp
     TaskbarButton.cpp
     TaskbarWindow.cpp
     WindowList.cpp
diff --git a/Userland/Services/Taskbar/ShutdownDialog.cpp b/Userland/Services/Taskbar/ShutdownDialog.cpp
new file mode 100644
index 0000000000..76799dd4e1
--- /dev/null
+++ b/Userland/Services/Taskbar/ShutdownDialog.cpp
@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "ShutdownDialog.h"
+#include <AK/String.h>
+#include <AK/Vector.h>
+#include <LibGUI/BoxLayout.h>
+#include <LibGUI/Button.h>
+#include <LibGUI/Label.h>
+#include <LibGUI/RadioButton.h>
+#include <LibGUI/Widget.h>
+#include <LibGfx/Font.h>
+#include <LibGfx/FontDatabase.h>
+
+struct Option {
+    String title;
+    Vector<char const*> cmd;
+    bool enabled;
+    bool default_action;
+};
+
+static const Vector<Option> options = {
+    { "Shut down", { "/bin/shutdown", "--now", nullptr }, true, true },
+    { "Restart", { "/bin/reboot", nullptr }, true, false },
+    { "Log out", {}, false, false },
+    { "Sleep", {}, false, false },
+};
+
+Vector<char const*> ShutdownDialog::show()
+{
+    auto dialog = ShutdownDialog::construct();
+    auto rc = dialog->exec();
+    if (rc == ExecResult::ExecOK && dialog->m_selected_option != -1)
+        return options[dialog->m_selected_option].cmd;
+
+    return {};
+}
+
+ShutdownDialog::ShutdownDialog()
+    : Dialog(nullptr)
+{
+    resize(180, 180 + ((static_cast<int>(options.size()) - 3) * 16));
+    center_on_screen();
+    set_resizable(false);
+    set_title("SerenityOS");
+    set_icon(Gfx::Bitmap::load_from_file("/res/icons/16x16/power.png"));
+
+    // Request WindowServer to re-update us on the current theme as we might've not been alive for the last notification.
+    refresh_system_theme();
+
+    auto& main = set_main_widget<GUI::Widget>();
+    main.set_layout<GUI::VerticalBoxLayout>();
+    main.layout()->set_margins({ 8, 8, 8, 8 });
+    main.layout()->set_spacing(8);
+    main.set_fill_with_background_color(true);
+
+    auto& header = main.add<GUI::Label>();
+    header.set_text("What would you like to do?");
+    header.set_fixed_height(16);
+    header.set_font(Gfx::FontDatabase::default_bold_font());
+
+    for (size_t i = 0; i < options.size(); i++) {
+        auto action = options[i];
+        auto& radio = main.add<GUI::RadioButton>();
+        radio.set_enabled(action.enabled);
+        radio.set_text(action.title);
+
+        radio.on_checked = [this, i](auto) {
+            m_selected_option = i;
+        };
+
+        if (action.default_action) {
+            radio.set_checked(true);
+            m_selected_option = i;
+        }
+    }
+
+    auto& button_box = main.add<GUI::Widget>();
+    button_box.set_layout<GUI::HorizontalBoxLayout>();
+    button_box.layout()->set_spacing(8);
+
+    auto& ok_button = button_box.add<GUI::Button>();
+    ok_button.on_click = [this](auto) {
+        done(ExecResult::ExecOK);
+    };
+    ok_button.set_text("OK");
+
+    auto& cancel_button = button_box.add<GUI::Button>();
+    cancel_button.on_click = [this](auto) {
+        done(ExecResult::ExecCancel);
+    };
+    cancel_button.set_text("Cancel");
+}
+
+ShutdownDialog::~ShutdownDialog()
+{
+}
diff --git a/Userland/Services/Taskbar/ShutdownDialog.h b/Userland/Services/Taskbar/ShutdownDialog.h
new file mode 100644
index 0000000000..73f581916c
--- /dev/null
+++ b/Userland/Services/Taskbar/ShutdownDialog.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/Vector.h>
+#include <LibGUI/Dialog.h>
+
+class ShutdownDialog : public GUI::Dialog {
+    C_OBJECT(ShutdownDialog);
+
+public:
+    static Vector<char const*> show();
+
+private:
+    ShutdownDialog();
+    virtual ~ShutdownDialog() override;
+
+    int m_selected_option { -1 };
+};
diff --git a/Userland/Services/Taskbar/TaskbarWindow.cpp b/Userland/Services/Taskbar/TaskbarWindow.cpp
index 0f9d80ba32..b2b027e4d6 100644
--- a/Userland/Services/Taskbar/TaskbarWindow.cpp
+++ b/Userland/Services/Taskbar/TaskbarWindow.cpp
@@ -36,9 +36,11 @@
 #include <LibGUI/Desktop.h>
 #include <LibGUI/Frame.h>
 #include <LibGUI/Icon.h>
+#include <LibGUI/Menu.h>
 #include <LibGUI/Painter.h>
 #include <LibGUI/Window.h>
 #include <LibGUI/WindowServerConnection.h>
+#include <LibGfx/FontDatabase.h>
 #include <LibGfx/Palette.h>
 #include <serenity.h>
 #include <stdio.h>
@@ -69,7 +71,8 @@ private:
     }
 };
 
-TaskbarWindow::TaskbarWindow()
+TaskbarWindow::TaskbarWindow(NonnullRefPtr<GUI::Menu> start_menu)
+    : m_start_menu(move(start_menu))
 {
     set_window_type(GUI::WindowType::Taskbar);
     set_title("Taskbar");
@@ -82,6 +85,17 @@ TaskbarWindow::TaskbarWindow()
     main_widget.set_layout<GUI::HorizontalBoxLayout>();
     main_widget.layout()->set_margins({ 3, 2, 3, 2 });
 
+    auto& start_button = main_widget.add<GUI::Button>("Serenity");
+    start_button.set_font(Gfx::FontDatabase::default_bold_font());
+    start_button.set_icon_spacing(0);
+    start_button.set_fixed_width(80);
+    auto app_icon = GUI::Icon::default_icon("ladybug");
+    start_button.set_icon(app_icon.bitmap_for_size(16));
+
+    start_button.on_click = [&](auto) {
+        m_start_menu->popup(start_button.screen_relative_rect().top_left());
+    };
+
     create_quick_launch_bar();
 
     m_task_button_container = main_widget.add<GUI::Widget>();
diff --git a/Userland/Services/Taskbar/TaskbarWindow.h b/Userland/Services/Taskbar/TaskbarWindow.h
index 9e0e73878d..e88309c55c 100644
--- a/Userland/Services/Taskbar/TaskbarWindow.h
+++ b/Userland/Services/Taskbar/TaskbarWindow.h
@@ -39,7 +39,7 @@ public:
     static int taskbar_height() { return 28; }
 
 private:
-    TaskbarWindow();
+    explicit TaskbarWindow(NonnullRefPtr<GUI::Menu> start_menu);
     void create_quick_launch_bar();
     void on_screen_rect_change(const Gfx::IntRect&);
     NonnullRefPtr<GUI::Button> create_button(const WindowIdentifier&);
@@ -50,6 +50,7 @@ private:
 
     virtual void wm_event(GUI::WMEvent&) override;
 
+    NonnullRefPtr<GUI::Menu> m_start_menu;
     RefPtr<GUI::Widget> m_task_button_container;
     RefPtr<Gfx::Bitmap> m_default_icon;
 };
diff --git a/Userland/Services/Taskbar/main.cpp b/Userland/Services/Taskbar/main.cpp
index 02cc6a0af8..04e743dadc 100644
--- a/Userland/Services/Taskbar/main.cpp
+++ b/Userland/Services/Taskbar/main.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -24,14 +24,29 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include "ShutdownDialog.h"
 #include "TaskbarWindow.h"
+#include <AK/Debug.h>
+#include <AK/LexicalPath.h>
+#include <AK/QuickSort.h>
+#include <LibCore/ConfigFile.h>
+#include <LibCore/DirIterator.h>
 #include <LibCore/EventLoop.h>
+#include <LibDesktop/AppFile.h>
+#include <LibGUI/ActionGroup.h>
 #include <LibGUI/Application.h>
+#include <LibGUI/Menu.h>
+#include <LibGUI/WindowServerConnection.h>
+#include <serenity.h>
 #include <signal.h>
+#include <spawn.h>
 #include <stdio.h>
 #include <sys/wait.h>
 #include <unistd.h>
 
+static Vector<String> discover_apps_and_categories();
+static NonnullRefPtr<GUI::Menu> build_system_menu();
+
 int main(int argc, char** argv)
 {
     if (pledge("stdio recvfd sendfd accept proc exec rpath unix cpath fattr sigaction", nullptr) < 0) {
@@ -51,8 +66,170 @@ int main(int argc, char** argv)
         return 1;
     }
 
-    auto window = TaskbarWindow::construct();
+    auto menu = build_system_menu();
+    menu->realize_menu_if_needed();
+
+    auto window = TaskbarWindow::construct(move(menu));
     window->show();
 
     return app->exec();
 }
+
+struct AppMetadata {
+    String executable;
+    String name;
+    String category;
+};
+Vector<AppMetadata> g_apps;
+
+struct ThemeMetadata {
+    String name;
+    String path;
+};
+
+Color g_menu_selection_color;
+
+Vector<ThemeMetadata> g_themes;
+RefPtr<GUI::Menu> g_themes_menu;
+GUI::ActionGroup g_themes_group;
+
+Vector<String> discover_apps_and_categories()
+{
+    HashTable<String> seen_app_categories;
+    Desktop::AppFile::for_each([&](auto af) {
+        g_apps.append({ af->executable(), af->name(), af->category() });
+        seen_app_categories.set(af->category());
+    });
+    quick_sort(g_apps, [](auto& a, auto& b) { return a.name < b.name; });
+
+    Vector<String> sorted_app_categories;
+    for (auto& category : seen_app_categories) {
+        sorted_app_categories.append(category);
+    }
+    quick_sort(sorted_app_categories);
+
+    return sorted_app_categories;
+}
+
+NonnullRefPtr<GUI::Menu> build_system_menu()
+{
+    const Vector<String> sorted_app_categories = discover_apps_and_categories();
+    auto system_menu = GUI::Menu::construct("\xE2\x9A\xA1"); // HIGH VOLTAGE SIGN
+
+    // First we construct all the necessary app category submenus.
+    HashMap<String, NonnullRefPtr<GUI::Menu>> app_category_menus;
+    auto category_icons = Core::ConfigFile::open("/res/icons/SystemMenu.ini");
+    for (const auto& category : sorted_app_categories) {
+        if (app_category_menus.contains(category))
+            continue;
+        auto& category_menu = system_menu->add_submenu(category);
+        auto category_icon_path = category_icons->read_entry("16x16", category);
+        if (!category_icon_path.is_empty()) {
+            auto icon = Gfx::Bitmap::load_from_file(category_icon_path);
+            category_menu.set_icon(icon);
+        }
+        app_category_menus.set(category, category_menu);
+    }
+
+    // Then we create and insert all the app menu items into the right place.
+    int app_identifier = 0;
+    for (const auto& app : g_apps) {
+        auto icon = GUI::FileIconProvider::icon_for_executable(app.executable).bitmap_for_size(16);
+
+        if constexpr (SYSTEM_MENU_DEBUG) {
+            if (icon)
+                dbgln("App {} has icon with size {}", app.name, icon->size());
+        }
+
+        auto parent_menu = app_category_menus.get(app.category).value_or(*system_menu);
+        parent_menu->add_action(GUI::Action::create(app.name, icon, [app_identifier](auto&) {
+            dbgln("Activated app with ID {}", app_identifier);
+            const auto& bin = g_apps[app_identifier].executable;
+            pid_t child_pid;
+            const char* argv[] = { bin.characters(), nullptr };
+            if ((errno = posix_spawn(&child_pid, bin.characters(), nullptr, nullptr, const_cast<char**>(argv), environ))) {
+                perror("posix_spawn");
+            } else {
+                if (disown(child_pid) < 0)
+                    perror("disown");
+            }
+        }));
+        ++app_identifier;
+    }
+
+    system_menu->add_separator();
+
+    g_themes_group.set_exclusive(true);
+    g_themes_group.set_unchecking_allowed(false);
+
+    g_themes_menu = &system_menu->add_submenu("Themes");
+    g_themes_menu->set_icon(Gfx::Bitmap::load_from_file("/res/icons/16x16/themes.png"));
+
+    {
+        Core::DirIterator dt("/res/themes", Core::DirIterator::SkipDots);
+        while (dt.has_next()) {
+            auto theme_name = dt.next_path();
+            auto theme_path = String::formatted("/res/themes/{}", theme_name);
+            g_themes.append({ LexicalPath(theme_name).title(), theme_path });
+        }
+        quick_sort(g_themes, [](auto& a, auto& b) { return a.name < b.name; });
+    }
+
+    auto current_theme_name = GUI::WindowServerConnection::the().send_sync<Messages::WindowServer::GetSystemTheme>()->theme_name();
+
+    {
+        int theme_identifier = 0;
+        for (auto& theme : g_themes) {
+            auto action = GUI::Action::create_checkable(theme.name, [theme_identifier](auto&) {
+                auto& theme = g_themes[theme_identifier];
+                dbgln("Theme switched to {} at path {}", theme.name, theme.path);
+                auto response = GUI::WindowServerConnection::the().send_sync<Messages::WindowServer::SetSystemTheme>(theme.path, theme.name);
+                VERIFY(response->success());
+            });
+            if (theme.name == current_theme_name)
+                action->set_checked(true);
+            g_themes_group.add_action(action);
+            g_themes_menu->add_action(action);
+            ++theme_identifier;
+        }
+    }
+
+    system_menu->add_separator();
+    system_menu->add_action(GUI::Action::create("Run...", Gfx::Bitmap::load_from_file("/res/icons/16x16/app-run.png"), [](auto&) {
+        pid_t child_pid;
+        const char* argv[] = { "/bin/Run", nullptr };
+        if ((errno = posix_spawn(&child_pid, "/bin/Run", nullptr, nullptr, const_cast<char**>(argv), environ))) {
+            perror("posix_spawn");
+        } else {
+            if (disown(child_pid) < 0)
+                perror("disown");
+        }
+    }));
+    system_menu->add_action(GUI::Action::create("About SerenityOS", Gfx::Bitmap::load_from_file("/res/icons/16x16/ladybug.png"), [](auto&) {
+        pid_t child_pid;
+        const char* argv[] = { "/bin/About", nullptr };
+        if ((errno = posix_spawn(&child_pid, "/bin/About", nullptr, nullptr, const_cast<char**>(argv), environ))) {
+            perror("posix_spawn");
+        } else {
+            if (disown(child_pid) < 0)
+                perror("disown");
+        }
+    }));
+    system_menu->add_separator();
+    system_menu->add_action(GUI::Action::create("Exit...", Gfx::Bitmap::load_from_file("/res/icons/16x16/power.png"), [](auto&) {
+        auto command = ShutdownDialog::show();
+
+        if (command.size() == 0)
+            return;
+
+        pid_t child_pid;
+        if ((errno = posix_spawn(&child_pid, command[0], nullptr, nullptr, const_cast<char**>(command.data()), environ))) {
+            perror("posix_spawn");
+        } else {
+            if (disown(child_pid) < 0)
+                perror("disown");
+        }
+    }));
+
+    return system_menu;
+}