Comic (and current funniest) Louis C.K. appeared on the "Tonight Show" last night, and not even the tame Leno audience could hold him down. There to promote his new show, which premieres next week and is hilarious, C.K. ranted about the "motherf--kers" he has to deal with volunteering at his daughter's school. And yes, those "motherf--kers" are the other children.