Circuit board business cards have been done. But since circuit boards are, literally, my business, I felt that I needed one too. Of course it also had to be special. Research and experimentation took a long time with this one and the design even sat dormant, ready, for a while before I sent it out to fab.
The concept was to have throug-hole components embedded within the PCB and soldered lying down. The components -- two resistors, LED, nChannel MOSFET, and a capacitor -- form a complete circuit so that when voltage is applied, the LED turns on.
It's meant to be an engineer's emergency kit. When all hope is lost, the MacGuyver engineer could snap out one of the components and save the day. Recall the countless times you desperately needed a 1 KOhm resistor to fix an amplifier at a party, only to see the girl you were trying to impress slip away with an OCaml programmer? Never again with this little kit. You even have 2 cm of solder in there to make sure the connection's electrically solid!
Consider the times when you were too drunk to recall Ohm's Law, yet was called in to fix a spaceship's control system. V=IR is written on the board to rescue you into awesomeness in spite of your inebriated state.
For those extreme situations when you need a Winston Wolfe my details are there so you know who to contact when the going gets tough. Finally, as motivation, my disapproving mug is there to stare at you as you're going about your engineering super hero day.
Now I only need to figure out how to manufacture this design cheaply enough so I can actually give those kits away ;)
(Oh, this is an open source design! The source files are at the usual place in the PCBmodE repository.)