Keep in mind that they may not be playing live also.
In our old band we were all midi'd up. I'd do a summersault and play my guitar behind my head at a certain point in the show, but the whole thing was triggered by MIDI so I didn't screw up.
Just for the hell of it though I'd show I was screwing people around by stopping halfway through a solo and solving a Rubics Cube or grabbing a hand puppet to do my vocals.