I settled on using my Raspberry Pi with the PiFace GPIO shield for inputs. Initially I was going to use the Pi for the GUI and an Arduino for the input processing. My thinking was the Arduino could constantly monitor the inputs while the RPi did other things. But it turns out the RPi was fast enough to do both, so the end result was much easier to deploy.
The wiring is pretty darn simple. Dry contact switches to the PiFace digital inputs. I used cheap speaker wire for the runs.
The switches all share a common ground. I had an old terminal block lying around that made this a piece of cake.
eBay from China for about $0.50 each. Perfect trivia grips.
The completed, and final, buzzers (yes, I know what it looks like).Python and used PyGame to handle all the graphics and input handling. The game is written such that the buzzers could be simulated with 1-4/5-8 for inputs so I didn't need a PiFace for local testing.
The source for the game is available here: https://github.com/SandyWalsh/trivia-box/tree/master/pi
It's a hack, so please excuse the mess. Patches welcome. There is so much more we can do with it. I have a YouTube video of the game play further down.
Then I set up for game night. Two teams of four players battle at any one time. Forty questions per game. Double elimination ladder for the full tournament. We had 8 couples (4 teams) which took about 3hrs to play through.
I asked the questions, so I was stationed at the end of the table. The RPi was plugged into a projector, then I had amplified speakers for sound and a keyboard for controlling the flow of questions. It's a console app, so no mouse needed.
My wife took care of all the other hosting duties ... here is the sugar cookie tray :)
the source README file.
It was a great night. Everyone had a ball and the software/hardware worked perfectly. There is a lot more I could do with it. I'd especially like to do more around the tournament management ... controlling the win/lose status and the double elimination ladder.