Pshaw, you only need a single weekend. The Global Game Jam was freakin' sweet, my only regret is that I was unable to deliver some musics to Seppuku in time for NaGaCremo because of it.
Our team was called Fishkabob, and we made a game with the sort of uninspired title "Deceptive Platformer." The theme for this year was deception, and the constraints for our time zone were "Rain, a plain, or Spain".
The gameplay revolves around switching the orientation of the game and the control scheme depending upon different platforms you land on. Also, some platforms will shoot you off in various directions, and there are little tokens that will flip the scene upside down.
It's not a TGC product (it's Flixel and ActionScript 3), but here's a
link anyways to our GGJ profile. Unfortunately, we're still working out the kinks of packing embedded .swf files in a single .swf you can play in your browser, so you won't be able to see the cool intro screen or the credits. BUT the gameplay is still there. Aside from chiming in on various design decisions, my primary focus was on audio and music. The music runs as a 4 bar loop that changes in time with the level change, accompanied by a short drum fill. I had plans to scale back the music if the player kept dying, but we ran out of time to flesh that out. The game was voted Best Overall Game at the NYU Jam site.