There is a perfect trick, which you can play on your colleagues. You know, when people work together for a long time they are usually tired and want to cheer up the working atmosphere.
I can tell you one checked joke, which you will certainly like.

Morning. As co-workers comes at the office, people in the room start to discuss the idea that it is impossible to come in the room 22 times during a minute closing the door each time. Usually somebody says that it is not that difficult and then colleagues offer him to bet. They bring in watches, on-lookers gather near the door and the action starts. A poor person runs in and out when everybody are shouting that he should close the door tightly. Time is running out, the tension grows… The person, of course, wins. A tired hardly breathing exited man turns to the colleagues with a question "I'm a winner, yeah?", and they, trying to hide satisfaction of a perfect free show, with absolutely indifferent and bored look answer without any