I loved building model kits when I was younger, but it never dawned on me how fun it would be to combine a Tamiya 1/16 kit of a WWII German King Tiger tank with a couple of miniature Regner Piccolo steam engines and a 3.5" marine boiler. This brilliant machine uses 100% steam propulsion, relying on batteries only for remote control and lighting.
The tank is controlled using a traditional 6-channel radio control unit, although the R/C receiver is a custom designed circuit board. All in all, this a brilliant machine. My only regret is that there aren't more of them. A nice little British Cromwell might prove to be an excellent adversary.