Cubelets are robotic building blocks with sensors, feedback, motors and power. With these blocks you can create robots that react and interact to the world around them. These kits are sold by ModRobotics and are available for pre-order for $160 which is a bit pricey, but the blocks do have some interesting qualities.
The entry level kit includes six Cubelets, with 2 sensors, 2 action blocks, and 2 brains including a battery pack. A giant robotic Cubelets kit costs $520 and includes 20 pieces. They’re made for kids eight and up and run on rechargeable batteries. I can see where these would be interesting for a while, but over time they would seem limited.