Meet the LightUp Edison Kit: an educational kit that helps you teach your children about electronics. It has magnetic blocks that you can connect to build circuits quickly. The iOS app for this kit not only provides you with ideas, it also has an augmented reality feature that lets you see the flow of electricity.
You get Rechargeable Battery, Red LED, Buzzer, Light Sensor, Momentary Switch, 50k Variable Resistor, and other blocks in this kit. It is possible to upgrade to build even cooler gadgets. You can find more information here.