http://www.gameyard.com/online/bubbles
It's a simplistic type of game but it does take a little while to figure out the strategy for best results. There is a random element as you cannot predict the layout of the colored bubbles when you exceed the maximum number of 'fouls' (fail to clear any bubbles).
The best I've been able to achieve so far is 161,000.
I like these kind of puzzle/strategy arcade-type games. Gameyard.com is a good source for them. I got my other favorite addictive time-waster (Tetris) from the same site.
Now if I could just find a good free version of Mahjongg...
