A co-worker's birthday celebration is a nice way to break up the monotony of the workplace while enhancing camaraderie. Some of the most fun celebrations include good-natured birthday pranks that give everyone in the office a chance to get in on the joke. The best ideas for an office birthday prank are fun, funny, easy to do and won't distract too much from a day's work and business.
For this prank, arrive at work early (or stay late the night before) and wrap the objects in his office or cubicle as if they were gifts. Include objects like his chair, computer mouse, keyboard, monitor, and office supplies. You can take this joke as far as you like for greater comedic value, even going as far, say, as to individually wrap individual pens, manuals, or items in desk drawers. Bear in mind, of course, that the "annoyance factor" can be pretty high with this prank, so be sure to temper that by including a real wrapped gift along with all the fake ones.
If one of your co-workers has a closed office space (rather than a cubicle or desk in an open area), rent a helium tank and use it to fill her office with inflated balloons. For best effect, do this one in the morning before work, since the balloons will loose much of their lift overnight. If you have the dedication to fill the room so full that balloons come spilling out as soon as she opens her door, you can ensure that the whole office will be instantly appreciative of the birthday prank.
Happy Birthday Business Call
If your co-worker is in charge of answering phones, leave the office and dial his line directly to deliver a fun or funny "happy birthday" message of your choosing. For best results, come up with the most absurd and off-the-wall fake call you can think of and try to get your colleague to crack up. End with a birthday salutation and maybe even some directions on where he can go to get a gift or card from the whole team.
Empty Office and Breakfast
If your work schedule will allow, and if your office is in the habit of closing up for the sake of celebrations, plan with your co-workers to leave the office empty when your co-worker arrives in the morning. Combine this with a surprise birthday breakfast where you're all waiting in the break room. Leave a note on her desk telling her to come to last-minute meeting to set up the surprise.