One time, when on a train ride with my Mum, I would solve the cube, pass it to her and she'd muck it up and pass it back to me to solve again. This went on for about half an hour in silence (god I love my mother - it was actually quite a bonding experience), before a woman who had been watching me (apparently for the entire time, I was informed later), asked me if I was very good at maths. I'm a bit weird when people talk to me when I'm not expecting it so I just stared at her for a bit before laughing and shaking my head. "Well you must be," she continued, "That's pretty amazing."
Either I looked very young or she thought I was a bit 'special' becasue she said it in the way I talk to the kids I babysit, but I nevertheless felt quite chuffed. Well, I wasn't going to be the one to break her illusion and explain that firstly, I actually suck at maths and that secondly, you can learn how to solve it by spending 20 mins on the Internet.
(Incidentally, I showed both my brothers how it's done and they quick smart went out and bought one so they too could seem like a maths/spatial genius. Drat. Now I'm going to have to learn how to speed-solve!)
So, conclusion? Rubik's cubes are great for stimming, just don't do it in lectures; the lecturer tends to get pretty annoyed.