Dunno if this is properly on-topic, but I did something entirely silly with DC electric engines last night.
I wanted to automate a large farm with just a few DC engines. I rigged up some projectred circuits (timer, pulser, repeater) in such a way that 4 dc engines (very slowly) built up charge in a coil, and then once very couple minutes, expended all that charge in a high-speed, decent torque blast of fans, so that I could harvest full rows (32 range) of crops.
This took me 2 hours to figure out because I'm terrible with projred circuitry. And really I could have just set up an array of way more DC engines. But...they're sort of cheaty? Challenge more or less accepted and overcome