Woot Shirt is currently selling a really great t-shirt, designed by Jack Anderson, that features the gastrointestinal system represented as a subway map.
You’re trying to get to the liver? See, what you wanna do is take the red line past the stomach, then switch trains at the small intestine. Green line’ll take you right there. Oh, you need to get to the appendix after that? Get back on the green line, back to the small intestine, switch to the red southbound, then get off at the large intestine station. The purple express goes right to the appendix. Whatever you do, stay off the blue line. It winds up in a pretty bad neighborhood.