Will the runaway success of Katamari Damacy spawn a "rolling things" genre? If it does, we're ready! Witness
Snowball, a compo game by Overkill, ustor, Ragecage, Troupe, and Darien
The plot of this game is not worth recounting, but the premise is cool: you roll a snowball around rough terrain, making it bigger and bigger and bowling over kids on your way to the stage end. Your snowball melts in warm areas, and you frequently need to use it as a platform to reach higher areas. There's not a lot here right now, since this was just a compo game, but I could easily see this being turned into a full game with nuanced areas and puzzles.
The physics is good -- everything feels very natural. I can't overstate how important that is in a game like this! It's kind of weird how you can end up pushing your snowball from the inside, but that's sort of necessary if you don't want it to obstruct you. Right now the only enemies are the children, and they just run back and forth, and while te terrain is wonderfully hilly, there isn't much to see in the levels. However, these are both things that could be improved in a full game. It would be swell to see more levels of this!