At first we thought: WTF? And then we thought: actually, this app is pretty damn clever. LookFor [1] (free) is an iOS and Android app that helps you find friends in a crowd. Select a color and hold the phone in the air, and a blinking light will guide your amigos to you. It's the thing you didn't know you needed for music festivals, parks, and general recreation. It could even help you hail a cab! It's so stupid, it's genius.