I started an escape room business for fun, and have been enjoying the heck out of writing custom software for the rooms. Both in-room and for administration.
My favorite is a javascript "OS" that I use to put imaginary windowed environments in the room, but the players never actually leave a full-screen browser.
It does full window management and all the regular UI stuff so it feels super normal to the players. My favorite part is that I don't use jQuery. That was just a little challenge I created for myself for fun.
Now my rooms have a login prompt of any kind, and I can then create windows with any kind of HTML/JS/CSS content for solving puzzles, extra clues, etc. I can use an RPi and control maglocks from the computer, light up LED's, or even communicate with wireless props.
I run a kiosk add-on for the browser and physically hack the keyboards so certain keys don't even work in the rooms. No F11 or Ctrl-Alt-Del without access to the netbooks or RPi's locked away in hidden compartments.
I also created a lot of room management software for timers, sending hints into the rooms on tablets, etc.