The ultimate test of whether you're a follower or not. In junior high, anyway...

"Two elephants are in two giant bathtubs, side-by-side. One elephant is washing himself down with soap, and the other one is listening to a portable radio. The one with the radio asks the one with the soap to pass the soap over. The one with the soap replies, 'NO SOAP, RADIO!'"

At this point, everyone in on the gag would start laughing hysterically. If the victim started playing along and laughing, you knew he was a follower and was just laughing because he thought everyone else thought it was funny. If he said, "Wait a minute, that's not funny!" or "I don't get it..." then the kid might just be alright.

Well, it was fun at the time...