Playing with toys alone is pretty fun I guess, but any kind of amusement is at its most amusing when you're subordinating your friends to the might of your will. Mattel's Radica Mindflex Duel does that. With your brain waves.
The original Mindflex was like playing basketball, but for your brain. Seriously, it read your brainwaves to move the ball. This new Mindflex Duel uses the same idea, but now you get to go head-to-head (or brain-to-brain) against a friend.
Mind-controlled toys are one of those little things that remind you we're sort of living in the future today (also: Disney FastPass). If you have some brain/computer schemes of your own, here's a thorough guide to hacking those toys.