There’s a price to it and the tag reads 10 bucks, but you might find that the fee is well worth it. Here’s one of the best samples:
“Setup two conference calls on two different machines. With one, call everyone’s desk phones. Act surprised, but suggest that it may just be a glitch in the building’s phone system. After the hubbub has started to die down, but before everyone else is back to work, hit the button to ring everyone’s cell phones. With a little acting on your part, you can have your co-workers calling for Mulder and Scully in a matter of minutes, but be sure to let them off the hook fairly quickly. This variant isn’t as much funny as it is terrifying. I’d only do this if I didn’t like my coworkers.”
More details are available here.