Ultrabear, a 2D platformer: http://code.google.com/p/ultrabear/
Screenshots: http://code.google.com/p/ultrabear/wiki/Screenshots
License: MIT License
It has a few bugs (falling through the ground), but is playable and seems to have quite a lot of levels.
Another program by the same person: http://code.google.com/p/congo-paint/