A mole made using Marc Dusseiller's DIY CAD method. The circuit is a little oscillator using a CD4093 quad nand-gate and a piezo buzzer. Touch the mole's hands (or underside in the 2 layer version) or stick it into the ground to change the sound and get the LED to blink.
To see a preview of the board and buy the parts go to the Kitspace page. Send the Gerbers to any PCB batching service to make your own. The top copper is also home etchable and the circuit works without any of the other layers.