http://ludumdare.com/compo/rules/
Theme: Entire Game on One Screen
This caught me by surprise, but the latest Ludum Dare has just started 45 minutes ago. The rules, briefly:
-Either enter the main event (the "Compo"): create game alone in 48 hours (pick any 2 days during the 72 hour window), creating all graphics, audio, maps, scripts, etc in that time. Using tools like bxfr is fine.
-Or enter the LD "Jam": create a game in 72 hours, possibly in a team and using preexisting resources
-Follow the theme
-Don't forget to create an account on the website to announce when you start your game



