An excellent trivia website with 91,000 quizzes and a total of 1,700,000 questions. They have 1,900,000 members but you can play without being a member. The quizzes are organised into categories such as history, geography and science. Here are a few sample quizzes:
On First Name Terms with British Bands
U.K. Shipping Forecast Areas Part I
Basics of Real Estate
This is also an excellent way for students to practise their English. Here is the website.