I've had my droid just randomly call people a few times when I wasn't touching the phone. I talked to two other Droid owners who were having the same problem. On said that the phone was on the seat next to her and just randomly called the 10th person in her call log. She never touched the phone, but heard the voice and the person wanted to know why she was calling. Something similar with the 3rd person.
My wife's does the same thing, we've had it sitting on the end table next to the couch and suddenly you'll hear someone going hello on it. She's phantom called me a few times now. Guess it's time for a visit to Verizon for number 3 for her.
I've noticed its done this a few times to me, but I think it was my own fault. I recently noticed that after I finished a call, I'd hang up and just put it in my pocket... not locking the screen. Now that I lock the screen, no problems yet... I think it was just hangin out in my pocket getting bumped and randomly deciding to invite the unsuspecting to a pocket privacy invasion party.
So, yeah... don't forget to lock your screen after you finish a call.