Statecharts
Lately at work I've been doing a few statecharts for things, so I thought I would repost the one I made last year that I did while completely bored last year. There's a cool program ("cool" being an extremely relative notion in this instance) you can get called graphviz that can create these things fairly quickly.
"Happy Times" State Transition Chart
I had a cool idea for a contest too I'm gonna blog about and get some participation in.