This site includes assorted fart and poop items
Some things are simply too obvious to list. The usual juvenile stuff is here including the timeless 'whoopee' cushions. If you've never encountered a whoopee cushion before, it comes with a graphic diagram indicating the suggested mode of use, like duuuh...
http://www.laughshop.com/lsstore/gag_gifts/index.htm
Yuk It Here