Surprisingly not an app that lets you watch choice scenes from that Amish Harrison Ford thriller, iWitness actually helps protect you from potential danger. For example, if you feel like murdery Danny Glover might be walking up behind you, tap the screen once to start recording video, audio, and GPS coordinates. Then, when you know he is, hit the screen again to trigger a 911 call, send an SMS/email message to six contacts, and set off a loud siren. Or simply trick the one dude he's with to go into the corn silo, get his shotgun, and waste Glover yourself.