Drive a Rover on Mars
Richard McElligott writes "Hi, the Active Robotics Lab at University of Reading has put up an online networked robot that can roam around a simulated martian landscape. All you need is sun java from www.java.com and you can view streaming online video and control the rover around the landscape using only your browser."
This is actually part of a very large network of control-it-over-the-internet rovers, called Red Rover. There's a handful listed here:
http://planetary.org/rrgtm/Rrsites.php