In September 2001 the British Association for the Advancement of Science (the BA) embarked on the world's largest, and most unusual, scientific experiment. The aim of the project was to find the world's funniest joke, and answer important questions about the psychology of humour. For example, Do men and women find the same jokes funny? Does our sense of humour change as we get older? What is the best time of day to tell a joke? Do different nations laugh at the same jokes? The experiment was called LaughLab and was carried out as part of Science Year in the UK. An Internet site was established containing two sections: in the first, people submitted their favourite jokes; in the second they answered a few simple questions about themselves - male or female, age, nationality, etc - and then rated how funny they found a random selection of jokes. The experiment captured the imagination of individuals throughout the world. 40,000 jokes were received and evaluated by 350,000 people. At the end of the project the information was carefully examined and discoveries made about the jokes that made men giggle and women groan, those that tickled kids but not adults, and the jokes that were the most popular in different countries. Along the way the 'winning' jokes in different categories were uncovered, including the best 'doctor' jokes