Sue's class is doing Venn Diagrams, so I thought I'd include a two more of my favorites. There are a ton of funny/cute uses of Venn Diagrams. It is definitely the one part of math that has stuck for every graphic designer.
Explain your next breakup with a Venn Diagram. Fuffer on Flickr
I call this the intersection of snarkiness.(You'll probably have to blow this one up to see it.)
This is pure wise-assery. Kevan on Flickr
Also, check out my personal favorite in this previous post.