My first jam was the Record Collection jam in January. I make games based on albums all the time anyway so it was just sort of a fun challenge to make a game in two weeks, but that gave me a taste of what jams can be and now I check the list all the time for other things that might inspire me.
I'm planning on putting together a Dog Jam in April. My pitbull Dude requires a pretty expensive hip bone surgery and I was joking about needing to make a really good game to pay for it, but some friends on twitter suggested a gang of us making dog-inspired games and now my brain is already spinning with the potential. Inspired by dogs, for dogs?!, BY DOGS?!, I think there is a lot of potential there.