Last night, I stumbled upon a cool little Flash game named Red.
The principle is similar to the old-school Missile Command game, but descending objects have gravity and you have 2 types of bullets to deflect the objects by pushing them away. New elements are introduced to the game play as you progress.
It is a nice little game that shows that simple game play can be enough to make a fun and addictive game. The good lounge-like music also helps.