I made 3D printed, Bluetooth connected, game show buzzers for playing The Voice at home, powered by Adafruit Circuit Playground Bluefruit boards and a laptop. Find the full story including build instructions in my blog post. Here it is in action:
Parts List
Code for the Bluefruit and the laptop are up on github.
First off, this is not going to win any mechanical engineering awards, but that's what you get when let the code monkey do CAD on a time crunch. Everything is "smash fit" and as such will be somewhat sensitive to your print tolerances.
Friction fit from the nuts hold the Bluefruit board in place. Add as many as you think are necessary.
Wiring is real simple. Only one of the key switches is actually connected (polarity doesn't matter), the others are just for mechanical support. I opted to use screws and nuts for the connections instead of soldering in case I wanted to repurpose the Bluefruit boards at some point, but of course soldering would work too - you do you. The key switch gets wired to the TX pin and any of the GND pins: