One of the cool presents under the Christmas tree this year was Makeblock's Starter Robot Kit. This kit contains everything you need to assemble your own robot tank and three wheeled car. The robot has rubber tracks for all-terrain mobility, an ultrasonic sensor for object avoidance, and an infrared remote control so you can drive it around the house, backyard, or classroom. It's all built around an arduino board, which allows you to program the robot, too.
A startup based out of Shenzhen, China, Makeblock produces a variety of other robotics kits in addition to the Starter Robot, using its open-source robiotics platform. As the name implies, you can get various add-on components to extend your robot into a unique technological creation.