The littleBits starter kit comes with 11 modules, including a power source, a vibration motor, pressure sensor, and various LEDs. Each kit costs $89, and you can also buy additional modules a la carte for about $20 each.
My idea was to have the robot's eyes light up by squeezing his hand. To do that, I used the following modules: battery + connector, power, wire, pressure sensor, and two RGB LEDs. You can adjust the color of the latter by using the included mini Phillips screwdriver and adjusting a little control on the module to make it more blue, green, or red.
Note, to make a circuit, all you need is a blue (power) and green (output) part. Pink and orange are optional.
Originally, I imagined having the robot wave with its left arm. However, there wasn't a part in the kit that would let me do that (there is a DC motor available for purchase separately, though), so I used the vibration motor instead. It just makes the arm shake a little and also produces a loud noise, but hey, you have to work with what you got, right?
And here he is! My littleBits, CNET-loving robot. He doesn't have feet, and I'm pretty sure his right arm is longer than his left, but I still love him. Now, I just need to think of a name. CNET's Donald Bell has thrown out Ghetto Robot, but I'm taking other suggestions.