I'm still betting on the gnomes. They may be trying to save electricity, or they may need the extra electricity for their experiments, because I'm willing to bet this particular house, with a steampunk and dieselpunk enthusiast, would attract the Tinker gnomes from Dragonlance.

The first theory is the most likely, and I don't think the housemate is lying about not turning the fan off. However, I can't entirely discount the fourth theory. Periodic limb movement disorder means I already move in my sleep. I just haven't shown that type of motor control while asleep sleep since childhood.

On the other hand, I was told that I was giggling in my sleep last night, and I'm pretty sure I haven't done that before either.