Scott Adam's 2-of-6 Rule

I'm really interested in humor, rules of comedy etc, i.e. what makes something funny. Scott Adam's 2-of-6 rule of thumb is very good. Check it out:
http://dilbertblog.typepad.com/the_dilbert_blog/2005/12/humor_formula.html

Cute (as in kids and animals)

Naughty

Bizarre

Clever

Recognizable (You've been there)

Cruel