cirque de soleil is like a circus, but full of contorionists... it's great music with great choreography (sometimes seen on Letterman). So some of it is funny, but most of is it just stunning (like 3 people doing a jump rope on their hands).
BLUE MAN GROUP!!! If you haven't noticed them on the Pentium commercials... tsk tsk tsk! I saw them before those when I was in Chicago and had a blast! I can't say much about it, but I can say that you must see b/c it's entertaining, fun, and full of brain stimulation, and even art work.