Here's some specific suggestions. I was most recently fascinated by this video on head tracking "virtual reality".

http://www.youtube.com/watch?v=Jd3-eiid-Uw

Another cool thing if you're into DIY robots (not really educational, but I found it inspiring) is the Yellow Drum Machine.

http://www.youtube.com/watch?v=_RyodnisVvU

Not sure why I got on the robot tangent but here's another good one, a 4-legged robot that's pretty good at navigating hills and obstacles. Especially the recovery from a fall sequence around 1:25.

http://www.youtube.com/watch?v=W1czBcnX1Ww

And here is hacking the Wii Fit controller and a Roomba to do a sort of vacuum-by-surfing... thing?

http://www.youtube.com/watch?v=tLbprdjTX0w&feature=relat...