Despite the hyperbolic ad imagery and bizarre name, the Joyboard Power Body Control wasn't really capable of sending kids into space or shaping and slimming busts and thighs. Similar in concept to the Wii Balance Board, but not nearly as sensitive, the Joyboard connected to the standard Atari joystick port and allowed a player to execute the cardinal joystick movements by standing on the board and leaning forward, back, left and right.
There was, however, no fire button support, which meant that only a few games could really be played this way -- Atari's Pac-Man and Ms. Pac-Man, perhaps, and the Mogul Maniac skiing game included with the Joyboard. I don't think Q*Bert would have worked very well this way, and I can't think of many other Atari 2600 games that completely ignored the single available button. I suspect Tigervision's Jawbreaker could be played sans button, as the ad specifically mentions enemy pickles.
The pack-in Mogul Maniac game is quite rare now, so the Joyboard was apparently a non-starter at retail. The ad copy urges kids to beg, borrow or save up for it, and warns potential fence-sitters:
DON'T WAIT. IT WON'T.
Which doesn't really mean anything I can think of, other than "we have a warehouse full of these furshlugginer Joyboards, and if they don't go out the door this Christmas, they're still gonna be sittin' here in February." Which, one gathers, they were.
Fortunately, the Amiga team survived this interesting misstep and went on to bigger things. Great minds learn from every opportunity, failure included.