http://www.sandfields.co.uk/games/
Brilliant site which does exactly what it says. My particular favourites are the Countdown clock whose settings can change depending on which mp3 file you link to. Also available are templates for certain quiz types. The Millionaire quiz is a flash template with an xml file that you can edit. There is also a template for playing Weakest Link and a PowerPoint for other quizzes.
I'll stick to 140 characters.... 