I pulled a good one on a thirsty coworker today. She's marshaling four -- FOUR! -- family members to devise a reciprocation. I wonder...
Although I enjoy playing practical jokes very much, I have my own code of conduct in this matter. After all, I want to ensure that the jokes are harmless enough that I can continue to play them 364 days a year. Therefore, here are a few of the guidelines that I use to design and execute a funny prank. Take what you like, leave the rest.
First, do no harm. Ever since that time in junior high PE when another girl pulled my shorts down to my knees, I have had no desire to do anything that would cause serious embarrassment or injury.
Second, who's gonna clean it up? Consider the end result. If you prop a cup on the top of a door, what will you have to pick up off the floor later? Marbles would make an amazing noise, but they'll roll away and perhaps pose a hazard to someone else. Either use a single tennis ball or find small lightweight objects that won't roll away.
Third, leave no marks. Need I say more?
Fourth, subtlety is most efficient. Elaborate set-ups are fine for special occasions, but most of my stuff is done on the fly. Time is of the essence if a person wants to remain in good standing with her supervisors. Initiate a casual conversation about rabid squirrels, right before you know someone is going to turn around and to find a stuffed animal staring them in the face.
Finally, weigh your options. Is this a "good" day to prank this particular person? How will he/she ultimately respond? Does the victim possess adequate maturity to refrain from whacking you over the head with the nearest baseball bat?
After running through all these rules of prankster etiquette, I knew how to *help* my coworker today. She was helping a family get library cards, and had a frog in her throat. We are not in the habit of having unsecured beverage containers in the library, but she didn't blink an eye when I showed up with a paper cup. In the back room, I had found a few little strips of clean paper. (Strips are easier to pick up than tiny confetti!) Coming around the side of her desk, in full view of her patrons, I tripped and spilled the "water" all over her lap. Riotous laughter ensued, witnesses provided safety against immediate retaliation, and a good time was had by almost all... But go back and read my opening paragraph again. If I suddenly sprout green feathers and squawk like a chicken, you'll know that my friend fixed me!