As a college instructor, I often enjoy doing review games - especially using PowerPoint for a Jeopardy! format. However, sometimes it's hard to see students' hands and the commercial buzzer systems are very expensive. I found a very basic game show circuit board at an electronics store, but the buttons were so small that it would never work for a team-style game. So I got the idea to use Staples Easy Buttons from another website that showed how to turn one into your garage door opener. These work great for team jeopardy because the entire team can sit around 1 button.
A few trips to Radio Shack and voila!
This is a lockout system, which means that once one person has pushed their button, it prevents anyone else from triggering their light. There is also a reset button for the moderator to "clear the board."
Total cost for a commercial system: ~$300
Total cost for this homemade option: ~$60
Bonus: I've attached a PowerPoint file that can be used as a Jeopardy template. All $$ on the main board are hyperlinked to the appropriate slide in the presentation. The small outlined arrow in the lower right corner of the home board links to final Jeopardy. I've also attached various Jeopardy .wav sounds for inclusion also.
Disclaimer: I am somewhat inexperienced with electronics parts/soldering - mostly self-taught - so I apologize for any sloppy work in the photos.