Parents of precocious modders with a penchant for DIY electronics will undoubtedly want to take a serious look at Hummingbird. Essentially, this is a DIY board manufactured by BirdBrain Technologies that is targeted specifically at kids. Interestingly, the company refers to the system as pre-Arduino.
The core component of Hummingbird is a custom controller that can be used to manipulate a variety of sensors, motors and lights. Many of these sensors and other components are included in the box with the Hummingbird controller. Getting started using the kit is as easy as connecting a pair of wires.
Hummingbird is also reasonably priced - starting at $199 for the kit - which includes the controller, a bunch of LEDs, a pair of vibration motors, four servos, and sensors for light, temperature, distance and sound. The company is also working on a kit with fewer components expected to sell for a cool $130. The little kit also has a power adapter, USB cable and a little screwdriver.
You can see all the components in the kit arranged on a display board in the video above. Personally, I think it's a very cool kit and can definitely see see kids (and adults) spending a lot of time modding the device. The company says that the parts and components are aimed at 5-7 grade skill level. Note: Hummingbird does require a constant connection to a computer.