Ghosts and goblins aren't the only ones with special powers on Halloween. Moms and Dads also dabble in sorcery -- transforming their offspring into all manner of fanciful creatures.

Of course it's always possible to pick up a standard, mass-produced costume.

But how much more fun to put together an original creation, using inexpensive and easily available materials. (What's more, your young Wonder Woman won't come home crestfallen because she encountered 10 other costumes exactly like hers.)

Construction paper, buttons, beads, fabric, old clothing, aluminum foil, cardboard and cardboard boxes, Mom's makeup and even grocery bags are some of the stuff of great get-ups.

Making Halloween outfits has become an annual tradition. Over the last 10 years I've turned son Ethan and daughter Elissa into everything from Mr. Spock and Cinderella's fairy god-mother to a pint-size upright piano made of two cardboard boxes. (The keyboard was cut from black and white construction paper; music came from a tape recorder.)

When they were small, I initiated most of the costume suggestions. But when they got to be 8 or 9, they took on the big decision-making part.

Since making Halloween costumes isn't my only job, I insist that projects stay relatively simple. If Elissa wants to be a paper-mache replica of the Starship Enterprise, she'd better start working with wheat paste and newspaper strips herself. And if Ethan insists on a bald eagle costume with 27 pattern pieces, I suggest he sign up for sewing lessons.

But even with my insistence on uncomplicated designs, we have managed to come up with some unusual costumes. Some samples:

Witch doctor : Fine for a 3-year-old. Take a grocery bag, cut generous holes for eyes, nose, arms. Let yourself go with such things as magic markers, knitting worsted for hair and construction paper for scary features.

Chess Piece : When our son developed a passionate interests in chess, he asked to be outfitted as a figure. Deciding that the rook would be the easiest, we drew and cut out the castle shape on a long, narrow cardboard box, adding an oval opening for his face and arm holes.

Rag Doll : Jeans and an oversize jacket stuffed with pillows, a cap to hold two large yellow yarn braids in place. We painted our daughter's face with exaggerated red lips and rouge circles on her cheeks.

Mr. Spock : Light blue pullover shirt (basted with a "Science Officer" emblem cut from felt), dark slacks, and boots. We made his oversized ears from pink construction paper, attached with transparent tape; exaggerated eyebrows with make-up pencil.

Fairy Godmother : Best party dress and good shoes, plus a wand made made from a wooden dowel wrapped in foil and topped with a foil-covered cardboard star. (For fun we also added a blond wig and a touch of lipstick.)

Superman : Blue tights, shorts and shirt, on which we basted a red and yellow felt "S" emblem. The cape: a piece of red broadcloth held around the neck with elastic.

Black Cats and Gray Mice: Tights, with matching shirts or leotards; construction-paper ears, make-up-pencil whiskers, and a tail of yarn.

Kids, of course, love any costume requiring a lot of makeup. One year mine gleefully turned themselves into aliens by smearing their faces with inexpensive purple eye shadow and attaching wire antennae to their hair with bobby pins. Quickly-sewn tunics of shiny, inexpensive lining fabric, black tights and boots completed the outfits.

It's not hard to come up with ideas for easy-but-imaginative Halloween costumes. And when you and the kids plan the projects and work on them together, it's a lot more fun for everyone.