The version that I made consisted of a simple oscillator circuit, as shown above. I was pretty happy with the idea that each person literally made up half of the circuit, however I overlooked the fact that the ground connections on each person had to be connected together. It was easy enough to solve this by placing them on a common metal 'ground', however it seemed a bit inelegant to me. Anyone have a suggestion for a better analog circuit to use? The requirements are that it has to break neatly into two parts, and that it will begin to oscillate when two wires are brought together. Bonus points if you construct it and give it to someone for Valentines day :-).