OK I guess I will be the first geeky entry. Hope this is ok.
As I say in my signature I live with a number (currently 6) of semi autonomous robots. They are mostly built out of stock parts from hobby shops or robotics websites but all have custom programming and some of the electronics are designed and made by myself.
The yellow one in the picture below is probably the oldest one I currently have being somewhere between 10 to 15 years old. That one was an experiment in programming an artifical insect.
The red one is more recent. He has bluetooth for digital communications (with my PC and subsequently my lights and appliances), a voice for vocal communication, a digital compass and PID motor control for navigation and sonar and IR for collision avoidance. Oh and the cat loves to play with him because he reacts to moving objects. Again all custom code.
Right that's my geeky Show and Tell, sorry they are not pretty but it is what I do when I am not reading.