Bloons - Today's Time-Waster
In the game Bloons, your goal is to pop all of the balloons on the screen by throwing darts at them. In each of the games 50 levels the balloons are arranged in a different order. With each level you are given a specific amount of darts to throw at the balloons (sometimes just one) and a target number of balloons you'll have to pop to move on to the next level.
Levels get progressively harder as you go on and start adding things like a bouncing wall, and walls you have to break through to get to the balloons. You also encounter "special balloons" which start effects such as giving you a boomerang rater than a dart to throw, or giving you the ability to throw three darts at once.