Well, I was checking out Planet Half-life out of bordum a while ago and came across this interesting video in the latest newspost.

http://www.brightcove.com/title.jsp?title=704328501

A company has developed a head piece that can read brain waves. To test the product, they simply created a mod for HL2 in which you levitate, pull, throw, or drop physics objects.

It's very interesting, I must say.