Kids who want to do a comedy act, but want the support and camaraderie of performing with friends can put together a sketch comedy act. Find sketches in comedy script books, or write your own sketch. Personalize existing sketches by placing them at a particular school or mention specific teachers. Keep the good-natured and do not make fun of anyone in a mean way. A show participant can create a stand-up comedy act by writing his own jokes or telling jokes from a joke book.
Music is an invigorating part of any talent show and performing a song in the right way can turn into a comedy act. A parody that turns an existing song into a funny number is a hilarious musical addition to a talent show. Channel Weird Al Yankovic and write new words to a favorite tune. Find a recorded instrumental version of the song and perform a funny parody with the new words. Kids do not have to know how to sing or play instruments to perform a lip-synced version of a song. Dress up as an outrageous band and lip sync to one of its songs while "air playing" instruments.
A child can delight a crowd with her well-rehearsed magic act and mystifying tricks. She can turn a magic act into comedy by adjusting some of the tricks. Instead of pulling a rabbit out of a big hat sitting on a covered table, pull out the head of a fellow student. Things going wrong on purpose can turn it into a hilarious comedy routine. The more the magician keeps a straight face, the funnier the outrageous mistakes will be.
Ventriloquism is a talent that takes years of practice. A ventriloquist performs with a dummy, or doll, and speaks for the dummy without moving his lips. Two children can turn this impressive skill into a hilarious routine with one kid being the ventriloquist and the other being the "dummy." Dress the "dummy" in a suit and draw lines from her mouth to her chin to look like a hinged jaw. The ventriloquist then talks to the dummy and the dummy talks in a funny character voice, making it seem the ventriloquist is talking.