I'm usually not a fan of games like Resco Bubbles, but I have to admit that this one is pretty addictive. The premise is simple:
blockquote>Resco Bubbles for iPhone/iPod Touch is an action puzzle game where the idea is to clear the grid of bubbles in order to advance to the next level. You are given a sequence of bubbles, which should be quickly and efficiently popped. Numerous explosive, speed-up, slow-down and damage bubbles keep the game play exciting and challenging.
[Thanks to Hobbes for the tip!]