I have a spider thats been doing some weird stuff lately too.
She went from being a pretty normal snake (a bit timid) into being totally crazy now (aggressive and really REALLY odd).
For example, when I went into the room I keep all our snakes in to grab something, I saw her moving around so I stopped to watch her and she's sitting on top of her hide with half her body straight up in the air just waving herself around. Like swinging back and forth, upside down, in circles, and almost falling off the hide when she leans backwards (upsidedown-ish). Pretty much just staring at the ceiling moving her head all over the place.
She's done stuff like this before, and it just looks really odd. One time when I was holding her (before she turned all nasty) she just flipped out and starting flopping around wildly.
Also now that she's decided to be a biter, her head starts shaking a lot when she gets into her little S curl to strike.
I honestly don't know whats up with her, but I was thinking maybe she's just a bit retarded?
I asked about on a dif. forum and was told to check this one out because appearently spiders are known for odd behavior..