Halloween is no longer just a time for kiddies to dress up like super heroes, witches, and ghosts to go trick-or-treating. According to the National Retail Federation, over 50 million adults will put on costumes and celebrate Halloween this year at grown-up parties -- including office gatherings.

Celebrating Halloween at work may sound harmless enough, but it can be loaded with pitfalls that could haunt your career. In fact, according to business etiquette expert Barbara Pachter, Halloween offers ripe opportunities for employees to make deadly image-busting mistakes.

A case in point: a pharmaceutical sales representative put on his Grim Reaper costume when he visited a hospital on Halloween. Neither the nurses, doctors nor seriously ill patients in the intensive care unit where he was spotted thought it was funny.

"Yes, it’s hard to believe, but this is a true story," says Pachter, author of the NewsRules@Work: 79 Etiquette Tips, Tool, and Techniques to Get Ahead and Stay Ahead, "People don’t always use common sense at work. This foolish act almost cost this sales representative his job."

So how do you serve up ghoulish fun at work without putting a curse on career plans? Event planners Patty Sachs and Phyllis Cambria (whose website www.partyplansplus.com is loaded with helpful party tips) say it’s a matter of planning your workplace Halloween party so that everyone is aware in advance of the kinds of costumes and activities that are appropriate.

Costumes: keep them simple (and reasonably tame)

Non-workplace Halloween parties for adults are often excuses to dress up in wildly outrageous and sexy costumes. Obviously, wearing a dominatrix outfit or a giant Viagra pill disguise isn’t appropriate for the office, even on Halloween. However, if you are in charge of planning a Halloween party, don’t assume everyone will use good business judgment when they choose a costume to wear to work.

"Adding the line ‘appropriate office costume attire’ to the invitation is a great way to get the word out. Or, if the office isn't too large, simply passing the suggestion by word of mouth should work," says party and event planner Cambria, author of Event and Party Planning Careers: The Ultimate Step-by-Step Guide to Success.

Pachter reminds employees that how you present yourself in the workplace -- including at Halloween office parties -- can impact your relationships with others and have consequences for your career. So she cautions opting for costumes on the conservative side. And she points out that you need to find out whether people are dressing up for Halloween for the whole work day or just for the party.

"Know what’s appropriate in your organization. Dress up only if others do, but don’t dress outrageously. One man was one of two in his whole company who dressed up and he felt awkward walking around disguised as a shark the whole day," Pachter says. "If in doubt, you can always just wear a mask or something easily removable."

Easy and not-too-far out Halloween office party costumes

One of the most fun things about Halloween is displaying creativity and humor with your costume choice, like the costume worn by the lawyer character played by actor Denzel Washington in the movie "Philadelphia."

"He simply wore a business suit with a lot of legal documents attached to it and went as a ‘law suit’," says Cambria.

Other ideas from Cambria for Halloween office party costumes that won’t break your budget and won’t spook your boss, either:

1. Check out clever and funny t-shirts available on-line. Or make your own with a permanent marker and some glitter. It can be as simple as a shirt proclaiming, "This IS my costume."
2. Wear a tropical print dress or shirt to work. When it's time for the party add a lei and a straw hat.
3. Go to work in jeans, a plaid shirt, and boots. Then don a cowboy hat, and you're all set to be a cowboy (or cowgirl) at party time.
4. A gypsy, pirate, or fortune teller outfit is easy to make using a flowing blouse and a peasant skirt. Then just pile on lots of beads, bracelets, and a head wrap for the party. Men can wear what Jerry Seinfeld called "a puffy shirt," an eye patch, tri-corner hat, and boots to create a pirate look -- with or without a plastic sword tucked into a wide belt.
5. Add a pocket protector to a white dress shirt and tape up the center of an old pair of glasses and you're a "nerd."
6. For a classic Halloween costume, dress in black for work, then add a witch's hat and a wide belt to transform into a witch for the office party.

Patty Sachs points out that Halloween office party planners can always skip the costume issue altogether by spreading the word that everyone should wear a hat that reflects their personality, passion, hobby, or talent. "This is quite entertaining as is, but when a bell rings or whistle blows, everyone must swap hats with another. And that is where the fun starts," says Sachs, author of The Complete Idiot's Guide to Throwing A Party (with Phyllis Cambria).

Treating your co-workers: easy but spooky decorations and refreshments

You can create quick and simple decorations for the event. Pumpkins are perfect accents for the room, but who has time to carve jack-o-lanterns? Cambria says it makes sense to use inexpensive plastic ones. She also suggests taping plastic or paper skeletons or black cat silhouettes cut from construction paper around the walls.

You can scatter a plastic skull or two and fake bugs and spiders on the tables for a touch of Halloween. But fake spider webs are not such a great idea; they can be hard to set up, or messy and difficult to remove.

How you serve refreshments can boost the ghost and goblin feeling. "For instance, use Halloween-themed bowls and platters. Plastic cauldrons are affordable, set a great mood, and can be used for everything from drinks to snacks," Cambria says. She notes that if you do get ambitious and carve a pumpkin, it can hold pumpkin soup, "and carved out gourds make great dip holders."

She also suggests these specifically themed Halloween goodies that are easy to make (for extra ghoulish fun, print the name of the dish on a label or index cards):

• Floating Eyeballs. Peel grapes and add them to orange or blood-red punch.
• Worms in Green Slime. Break up whole wheat spaghetti into short pieces, cook and serve with a thick green pesto sauce.
• Squirmy Drinks. Add some gummy worms to the rim of a punch bowl or freeze the candy worms inside real ice cubes.

Getting into the Halloween spirit without an office party

If there isn’t a Halloween party at your office or elsewhere on your social calendar, you can still have fun. Decorate your office or work cubicle for Halloween. Business etiquette expert Barbara Pachter advises clearing it with your boss first, however – and keep decorations on the tasteful side.

Sherry Baker is a freelance writer based in Atlanta, Georgia. She last wrote "Hello Health Care" for Synergy. Reach Sherry at featuredstories@adamcorp.com.