This one is for Andrew and for all the other Canabalt lovers out there. Robot Unicorn Attack is a Canabalt clone by Adult Swim Games.
As you might have guessed, instead of a man, you're a robot unicorn. You also have a few more controls. You can double-jump, and you can do a "rainbow dash" through giant star obstacles.
A lot of nice little touches both visually and aurally, but the thing that will continue to be with me throughout the rest of the day is the soundtrack, "Always" by Erasure.