This is a video of Backyard Brains co-founder Greg Gage hooking two people up with electrodes so anytime the woman thinks of moving her hand, she moves the man's hand as well. The system is available for purchase from Backyard Brains (which sells basic kits for people interested in neuroscience) for $260. Obviously, it probably can and should be modded into a fun sex toy for you and your partner. I don't know, get creative. Up the amperage and attach some of those electrodes to your privates, see what happens! Will your penis catch fire? Maybe. If it does though be sure to have a good excuse prepared for the ER doctors that doesn't involve hooking a science kit up to your nuts.
Hit the jump for the video demo, but skip around if you don't want to hear about science and just want to see dude's hand twitch.