I would see lots of yoyo's going through television screens.
No you wouldnt use a real yoyo but a virtual one would display on screen. Basically your character would be facing you and any movement you did would be replicated on screen. Tutorials would show you what hand gestures to do to create movements and to link trick combos and such. Tutorial would be basically like Simon says so you have to mimic what the trainer does first then copy it and then as you get better, you have to copy chain moves in unison. Battling online would be freestyle or Simon says or trying to copy a move the computer selects. Timing is key or else you drop the yoyo thus breaking combo chain and ensuing boos from the audience. Split screen co-op vs and online ranking and tournaments with voice chat.