Frank, Joe and Tom.
Funny story, actually. For a while, Joe wanted to be called Armatron, because he was fantastic at doing the Robot, but Frank and Tom wouldn't go along with it so Joe eventually gave up. They were like, "Joe, we're Magi, you have to stop doing the Robot. It was funny the first time, but now it's just getting kind of awkward." So Joe reluctantly agreed. He WAS damn good at the robot, though. No one could ever take that from him.
Later, it turned out that Joe had been severely dehydrated, so then the whole Armatron thing wasn't so funny after all.