Correction : I need this answer because I have this as part of my studies. Answer : I won't talk in detail but there was this instance when I was in college. Suddenly a friend who had a habit of being tense walked in and the others started telling him that there was a surprise test that afternoon. My friend was terrified and asked me how we knew. I played along and told him that we had heard the teacher talk to another teacher :P Needless to say, he was very worried and was angry at us for having fooled him when he realised that we were playing a prank on him :)

April 1st is April Fool's Day in Australia where it is traditional to play jokes on people. On one such occasion, I came to school as usual and a colleague said that he wanted to buy my car which he saw for sale on a sign in the staffroom. I said, "Sure you can, for $40,000!!" I played a long with his joke, until he admitted he'd put up the For Sale sign in our staffroom.