KDDI has a prototype Android app that can monitor your brainwaves. You have to wear a silly headband sensor and play an even dumber video game but the app graphs your brain's neural activity and concentration levels after you're done.

It's definitely cool to see how how engaged or brain-dead you are when doing a certain task, but I'd much rather control the video game with my brainpower than see how much (or little) brain I'm using. [Japan Trends via Engadget]