diff --git a/.gitignore b/.gitignore
index 075b1d4..fe33983 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,3 +8,4 @@
 !*.in
 !*.md
 !*.nix
+!*.nu
diff --git a/run.nu b/run.nu
new file mode 100755
index 0000000..17619a9
--- /dev/null
+++ b/run.nu
@@ -0,0 +1,17 @@
+#!/usr/bin/env nu
+
+# Run a specified AoC challenge.
+def main [
+  year_day_part_ext: string # The file to run. For example `2023/1-2.py` or `2023/1-2.nix`.
+] {
+  match ($year_day_part_ext | path parse | get extension) {
+    "nix" => {
+      nix eval (".#" + ($year_day_part_ext | str replace ".nix" ""))
+    }
+    "py" => {
+      cd ($year_day_part_ext | path dirname)
+      python $year_day_part_ext
+      cd -
+    }
+  }
+}