What is your favorite routine using 2 or more kids from the audience?
Be specific, don't just say "20th Century Silks". Please describe your setting too (bday party, stage show, etc.)

Example, mine is the Milk Funnel Trick on stage where you pour the milk into the kids ear and a girl "pumps" his arm to make the milk come out of his elbow. I use a 3rd kid on the side who holds up a hanky, every few moments I yell at him.."higher!" he holds it higher but inevitably moments later he brings it down again so he can see whats going on. At the high energy end of the routine, I finally take the hanky from kid 3 and wipe my brow with it and bow.

This is an ages old, but is still great even today!