10 cool tools for your mobile phone

Tapping and shaking your iPhone in time to music doesn't sound very useful, but it is addicting. Tapulous, the company that created Tap Tap Revenge, says iPhone users have downloaded its application more than 1 million times. The goal of the musical mobile game is to tap small bubbles that descend from three colored beams of light to the beat of a song. It's harder than it sounds.

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