Oh man, I'm glad this got bumped.
On another forum I used to go to, we had a thread "Shower Horror Stories", it was great. My favourite was the guy that was singing "I Believe in a Thing Called Love" by The Darkness in the shower, and decided to do some dance moves. He slipped, fell, and hit his head (can't remember what on or how hard).
I manage to stay pretty safe in the shower, although once, I was at a hotel, that had sliding glass shower doors. All of the steam built up inside the shower, to the point where I couldn't breath, and felt like I was going to pass out. Thankfully I was smart enough to open the door a crack and stick my head out.
The slipperiest thing I've ever slipped on in the shower is hair conditioner. And you don't even have to spill it. Just rinsing it out of your hair makes the bottom of the tub super slippery.