This is a follow up to a very successful guide I wrote in 2003 called "How To Tell If Your Friend Is Actually a Superhero":

How to Tell If Your Friend is Actually a Stand-Up Comic

1. Give her/him a microphone
2. Observe. If, during his/her routine, he or she periodically wanders back to the mic stand and absentmindedly grips and twists the microphone stand, he or she is probably a stand-up comic.