Zenly - Zenly is a GPS tracker to locate your friends in realtime.
Party with a Local - Party with a Local is a free app that connects travelers with locals that want to party.
ToT: ThisOrThat - Let your friends choose this or that for you
Babble - A more personalized social network
sup - The first creep-free way to see nearby friends
Palaround - Meet people you should be friends with.