I'm addicted to Drop7. I downloaded the puzzle game two months ago and there's absolutely no other game that's been dominating my iPhone. The simple premise - matching numbered balls before they fill the screen - is a near perfect balance of chaos and strategy. The methodical pace and savable games are perfect for mobile play, too. Do yourself a favor: Check out my review and, when you're done, download the free trial version through iTunes. Follow me on Twitter.