Primary at onemorelevel.com
Imagine there is no color in the whole world. Except for one man, determined to go Die Hard in an Office Building and bring all the colors back from the endless monochrome. He can change back and forth between the three primary colors, and each one has its own ability, which comes in useful when fighting the forces of (literal) darkness.
This game is pretty fun, although the controls are a bit fussy and take some getting used to. There's a lot of emphasis on wall-slide climbing on some levels, which can be endlessly frustrating, believe me. On the whole, though, I'd say it's a good way to kill some time.