Spontaneous Dialing

I woke up to my phone dialing the other night - at 3 am it was inches from my head on my nightstand. I hear it dialing a number that I programmed into it out of the blue. It was not bumped or moved in any way - just started dialing on it's own. Often it dials on it's own if it is in my purse or if I bump it by accident - never when it is just sitting there doing nothing. Anyone have this experience? Thanks!