I use to hack those Buzz! megaquiz USB controllers to wire up my own switches. I'd take apart one or two of those controllers(depending on how many buttons I need), jump the leads on the PCBs that closed the button circuits, and wire them to speaker terminals. Very primitive hacking for me, at the time. Then I'd use Joy2Key in the background. 5 1/2 years ago, I made a video on Youtube showing what I did. After word of mouth spread, I think I ended up making about 7 or 8 sets of these mods for people in the game show community. I quit making them, because it was starting to become too difficult to find the Buzz controllers.
Nowadays, I use much more durable and stronger equipment. If you're handy with wiring, look up I-Pac at
http://www.ultimarc.com No background software is needed. Wire up the buttons to the terminals on the board, plug and play, go. You can use a configuration tool that can be downloaded separately, to reassign the keystrokes to the board. Program it once, and it's burned right into to the board's firmware. For connectors...I typically now use XLR cables/jacks. They're more rugged.