This past weekend, I participated in "1 Class Jam".
Rather than a themed jam, this jam was a coding challenge. The objective: To create a game in a single class / structure, no subobjects. You can see my code on github.
The game I created was a simple turn-based card fighting game. I like the idea, although the execution (with the time limits of the jam) could use a little more balance and polish. I may continue on with this idea in the future.