Experimental Gameplay Project - Entertainment Technology Center, CMU

The Entertainment Technology Center at Carnegie Mellon is running an Experimental Gameplay Project wherein four grad students try to put out one game a week each during the course of a semester. Each week, a theme is announced, and the four students try to come up with a simple, fun game around that theme. Their games have to be made in less than seven days, and all art, sound, and programming is done by that student alone. All the games are archived for inspection, so if you're stumped for innovative gameplay elements, this might be a good place to look.