To have fun at work, you first need to create a to-do list not including times. Then, make use of useless time that involves waiting by entertaining yourself. For more tips, visit http://www.wikihow.com/Have-Fun-at-Work.
Business owners don't appreciate employees "having fun" at work if it's on the owner's dime. However, if you really enjoy the work you're doing in a job you love, you can have fun, please your employer, and get paid for the effort as well.