If you are in LA another place you might want to check out is the
"Clown Conservatory" in San Franscisco at he Circus Arts Center there. Their main thing is a year long program on clowning for any situation, but they also do workshops.
But alot depends on what kind of clowning you are interested in. The two big ones are circus/theater clowning and hometown clowning. There is alot of great crossover between the two, but if you want to get the most out of a camp or workshop, you should probably figure out which you are shooting for.