Buzztastic is a simple quiz program intended for use with groups, preferably using a video projector connected to your Mac. (I use it in my classroom to reinforce topics I have taught.)
Buzztastic is written in Objective-C using Cocoa. It requires OS X 10.3 (it may run on 10.4, but I've not tested it) and runs most happily at 1024x768.
Quiz questions are read from a plain-text CSV (comma-separated values) file and then presented one-by-one. Each question is shown for a user-definable time during which the points it is worth count down.
If a team chooses to answer during this time (by hitting their answer button) they are given a short time (also user-definable) to deliver their answer.
Buzztastic makes quizzes exciting due to the time pressures. My students like it!