There's a user-mod for Silent Hunter 5 (WW2 submarine simulation) which contains a fully working Enigma emulator for decoding and encoding messages. And with this mod installed, all orders from High Command come in encrypted and you'll have to learn and apply all the manual steps required for decoding to actually know what to do next in the game :)
I made a universal enigma machine simulator that includes a visualization of how the electric signal moves through the rotors and back. The rotors move too.
I kind of imagined it would make a nice 3d printer project, either printing ball-runs so ball-bearings represent current, or by somehow including conductors in the printing. If there is some glow-when-connected wire or wire with lots of tiny leds in, that would be awesome!
I've always felt conflicted about learning anything about these machines. They were part of such a terrible machine and were used to commit some awful crimes.
I have interest in Colossus and Bletchley Park though.
Here's a walkthrough video: https://www.youtube.com/watch?v=t-7-FrBU4fY
Good example of a video game that can also be educational, also a good case for keeping video games open enough so they can be modded by users.