http://mail.google.com/mail/help/motion.html

Amazing, I tell you! Pretty much the best thing to happen to email since carbon copy. Really! I love it to bits. Love it! For once I feel like I'm actually doing something productive with emailing. Once I got into it I actually was enjoying the controls. Only a little bit of calibration required with the webcam and you're good to go. Life should be controlled by motion like this piece of genius. Seriously, you should go try it yourself!