I like when his laugh loses all sound - very funny.Isn't it great how we'll make any bizarre and stupid noise necessary to get a laugh like that from a baby?*raises hand* Done it.
Oh, I totally do it. I visited my friend in Chicago and her two year old calls me Uncle Hooray because I'll do anything to make him laugh and then follow it with a Hooray!
Keep it clean, keep it classy, and jokes are always appreciated.