Cubris

Cubris is a flash-based puzzle game that is simple to learn, but can be difficult to solve. You control the little dude in the picture above. Your goal is to eliminate all the colored blocks by pushing them into groups of two or more so that they disappear. Like all games of this type, there are special cubes which make the game even more interesting. The best part about the game is that it's entirely web-based, no installation required. Quit reading and go check it out here.