Notch seems to be a pretty talented programmer in his own right, as he made this rather good dungeon crawling FPS game during the Ludum Dare competition in 48 short hours. The competition challenges designers to produce little games based around ambiguous terms like "addiction" and "adventure' and "slovenly" etc, and this year they ended up with 599 entries, which is kind of a weird number. You can play it here.
Minecraft’s Notch Made A Dungeon Crawler in 48 Hours!
Prelude of the Chambered, a game by Notch, was made in just under 48 hours and looks kind of neat.
