I went to the Indie Game Jam over the weekend with Ryan and Thatcher from Oddworld. It's a 4 day event, but we just went for 3 days, because we worked right up to it and have to resume working again. The theme this year was Physics, which was very tough. The first day I really struggled; I was tired from over-work, and couldn't really get any good ideas. The last day, I finally found a fun game mechanic and got into a good flow.