WHAT YOU'LL NEED:
-a friend who's in on the trick
WHAT THE TRICK LOOKS LIKE:
You and your friend tell the audience that you have a weak telepathic connection. To prove it, your friend will randomly pick someone from the audience, hold his hand over that person's head, and without looking, you will know who it is.
WHAT'S THE SECRET?
First you explain to the audience that you will need a few moments of silence so that you and your friend can establish the link.
You know how people are... Someone will caugh or laugh or make a wiseass remark. That's your signal! The FIRST person to make a vocal sound is the one your friend will hold his hand over in a few moments.
Before you start the trick, your partner will ask you: "Are you ready?" (What he's really asking you there is "Did you catch who made the first sound?")
If you answer no, you'll tell the audience to be quiet again, because you need to concentrate a little more... (and you wait for the first person to make a sound again.)
If you answer yes, you can proceed with the trick. Now you turn your back to the audience, so that you can't see what your partner is doing.
Your partner will walk through the audience and hold his hand over a few people's heads. And every time he will ask "Over?" and you will respond "Over."
After a few times, your partner will finally put his hand over the person you had silently agreed upon. Now your partner will ask "Over who?" and without looking, you will be able to answer with the name of that person (because it's the first person who had made a vocal sound earlier.)