Room 13 is one of the biology labs, situated on the balcony. It has one of those awesome plastic skeletons that are never used by teachers - not even when pupils are studying the skeleton. If you sit on the desk in front of it, it is kind of unnerving because it always feels like somebody is watching you. The poster behind it showing the muscles in the skull with massive eyes doesn't help either.
There lots of very strange pickled things floating in jars on the shelves in this room...
The desks in this room are ridiculous as they are like benches but only fit 2-3 people on each one, and you can't fit 3 bags, stools and 3 pairs of legs underneath one. The desks also have a lot of hearts and stick figures drawn on them.