Meet the littleBits Gizmos & Gadgets Kit: an educational kit for kids that comes with all the sensors and accessories needed to complete fun projects. It comes with fan, light sensor, buzzer, slide dimmer, servo, and other parts. The kit comes with 15 electronic building blocks and a handbook. You get instructions for 12 inventions right out of the box.
This educational kit is user-friendly but teaches your kids enough to prepare them for more complex DIY projects. More information is available here.