A game jam is an event where participants try to make a video game as quickly as possible. Most game jams take place over a single weekend, where everyone has 48 hours to try to make a game often based on a secret theme that is either voted upon or chosen by the organisers. The theme is used as a limitation that encourages creative thinking.
Hmm... I never been to a game jam (not that I was actively looking, but I *assume* they are going on in my area), but this really gave me a good third party perspective on what I thought went on and accounts from others.
A quick cursory google search came up with my area and ties to this recognized group: http://www.ludumdare.com/compo/
The giant list one one liner tips are crazy funny - not only for a jam, but when tackling other time constrained projects.
Aim for a smaller game that you hope to make. If you have extra time at the end you can add more features
I know a few of you out there have participated to some degree of success.. how'd it go?