Not sure if this was brought up before, but I've detected, over the past few months, that I've experienced periods of hyperactivity in my mind.
It generally happens when I'm trying to go to sleep, and then fail to do so. At that time my mind goes a a mile minute jumping from one possibility to the next after I just came up with an idea I liked.
My heart rate tends to accelerate, I think (I'll have to confirm that), and it's hard not to smile in excessive amounts over my idealistic ideas and the future repercussions that could result from it (which tend to be overly idealistic, as well.)
Or something along those lines. I thought it was sort of strange/interesting.