Flip2Mute can change your profile to Silent or Vibrate and TurnOff the screen when the phone is Faced Down. It has a simple user interface and can be installed on WVGA HTC devices. (Tested on Blackstone – Energy.BLACKSTONE.23569.Sense2.5.MaxSense.UI.May.3 0)

http://forum.xda-developers.com/showthread.php?t=694689

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