Here's a riddle:

What can you have for a small price that you play with for a while and then sit and look at it for hours?

Here's some hints:

It may cause high levels of exasperation until you either throw it away or let someone else use it and every household has at least one.

Think about it a little more.

And here's the answer:

A puzzle.

The concept of grownups playing with puzzles may seem inane, but not to a small group of professors and students from the Boston area. Recently, a couple of collectors joined the enclave in Dudley's Lehman Hall for the first annual "Puzzle Party," where they munched cookies and lemonade while playing mind games with one another. Literally.

In town for the opening of a touring puzzle exhibition at the MIT museum, the collectors added an air of professionalism to an otherwise casual event. The collectors arrived with a few puzzles of their own, imported from their massive stores of puzzles. Featured among the games were Rubik's Cubes, Chinese folding boxes, Indian peg games and other mind twisters from around the world.

The puzzle party was the brainchild of Jack Gray, a teaching fellow for VES 176, "Synergetics," a course on concepts in three-dimensional forms. "I heard through people on the West Coast that they had puzzle parties out there," says Gray. "So I thought, `Gee, wouldn't it be fun if we had one here?'"

Gray held a test party at his home before he hosted the one at Dudley House.

Much to Gray's surprise, however, East Coast puzzle solvers have a different style from those on the West Coast. Here, Gray relates, participants sit quietly and work on the puzzles, while on the West Coast, a puzzle party can turn into a rowdier affair.

"A friend called up on the phone and asked, `Where's the noise?'" Gray says. "A few drank beer but that was okay; they couldn't solve the puzzles."

The Lehman Hall gathering, held in the main dining hall, was also subdued. Like the party at Gray's house, students and faculty from many academic disciplines sat around tables and quietly fiddled with the puzzles they brought with them.

Gray says one of the reasons the party was held in Lehman Hall was that the head instructor of VES 176, Senior Lecturer on VES Arthur L. Loeb, is also the Master of Dudley House.

Although the party was publicized with only a few fliers and a notice in the Dudley House newsletter, many students, art professors and a couple of collectors who were to exhibit their puzzles at the MIT museum the following day showed up.

"I don't think anyone was bored," says Gray, who hopes to eventually host more puzzle parties.

Ten Thousand Puzzles Of...

But puzzle lovers do not have to wait for the next party before finding a mecca of games. The MIT museum is currently sponsoring an exhibit of an extravaganza of puzzles. Six rooms at the museum are devoted to puzzles; they comprise a unique genre including mathematics, painting, and sculpture, as well as some psychology.

Some puzzles, though packaged in new trimmings, have been around for centuries, according to the exhibit.

The exhibit depicts a wide variety of puzzles. On display is a puzzle more sophisticated than the now-ubiquitous jigsaw puzzle, known as a "tangram." The tangram, though used in many disparate cultures, appears in more or less the same form throughout China, Japan and Europe.

The premise is different from the jigsaw puzzle, which has one and only one solution. The tangram usually comes with a booklet (or in ancient China, several volumes) which are filled with pictures that the solver creates with the seven pieces with which he or she is provided.

Included in the exhibition is an example of the more practical applications of the tangram. During World War I the popularity of this puzzle provided a manufacturer with a chance to help Allied prisoners escape; Red Cross care packages contained tangram puzzles in wooden boxes, many of which had a hacksaw, a compass, and a map concealed in a false wall of the box.

Another puzzle that the exhibit depicts the long history of is the dexterity puzzle. This very simple puzzle--with four balls in a circular maze--caused a craze in the 1880s almost on the scale of the Rubik's Cube fad a century later. The object was to put the four balls in the center of the maze, or place the "pigs" in the "pen."

Other dexterity puzzles did not require the user to manipulate steel or stone balls, but water, mercury, or capsules with lead balls inside of them.

The exhibit details the chronology of these pieces. One puzzle, made in the image of the Atlantic Ocean, challenges players to put the "planes" of Lindbergh, Byrd, and Chamberlain into "hangars" located on the other side of the ocean. The puzzle pays tribute to the real-life race as to which of the three pilots would cross the Atlantic first.

Another dexterity puzzle required a fighter plane to "shoot down" a WWI-vintage zeppelin. But if the ball fell into a hole, the fighter itself was shot down--disappearing into a hole surrounded by a picture of a fireball.

One of the more eclectic type of puzzles in the exhibition are the "appearing/disappearing object" puzzles.

The immortal "geometric money" puzzle is one of the original types of this kind of puzzle. On first glance, it looks as though if you draw a diagonal line through a three-by-ten box and rearrange the pieces, you will wind up with a 32 square-inch field instead of a 30 square-inch field.

But appearances can be deceiving. Go see for yourself.

Attracting much attention from the exhibitgoers, was the "disappearing devil fan." A large replica is on display for people to try and figure out. Designed to rotate in a limited manner, the puzzle is created by fastening two concentric circles together. The idea is that when the puzzle is in its original position, you can count 13 devils. But when you rotate one of the circles just a little bit, one of the devils disappears.

The puzzle, of course, is to figure out how this happens.

The largest display in the exhibition is the collection of block puzzles, which are far from ordinary barrel puzzles.

Some of these block puzzles seem to be works of art as well as a challenge, made of cherry and rosewood, or combinations of fine woods varnished to a high lustre, so that they are almost too pretty to take apart.

Another "artistic" type of puzzle is the puzzle vessel. The idea is to try and find a way to drink the liquid from the vessel assigned to you without making a complete fool of yourself. Sounds simple, until you notice the holes in the sides of the cup near the lip of the vessel, making it impossible to drink in a normal manner.

Usually, the vessel has a secret siphon or straw in the handle (a remarkable feat of ceramic artisanship) with which the patron can imbibe.

But the most colorful type of puzzles (and the favorite of the viewers) are located in the "sequence puzzle" area. Such puzzles make you follow a precise set of rules to solve them.

One kind is the "shifting block" puzzle. One puzzle in the exhibition required the user to move a "car" through "traffic" or even use four "walls" to surround a "dinosaur."

Of course there are also examples of the 15-block puzzles which you now see sold in grocery stores as party favors. This kind of puzzle was actually invented in the 1890's and was used as a manufacturing and contest gimmick.

Four seperate displays are dedicated to three-dimensional geometric sequence puzzles. Perhaps the best-known and most obvious example of this kind is Erno Rubik's cube puzzle. That wonderful cuboid object, first marketed in the U.S. in the early 1980s, swept the globe, selling millions of copies in the process. It not only maddened the people who could not solve the easy-looking puzzle, but it spawned a generation of whiz-kids who could solve it in under a minute. Of course, some of these genuises wanted more. So manufacturers offered Cube spinoffs in odd shapes.

The exhibit has jazzed-up Cubes, with pictures of E.T., world flags, Prince Charles, and even Chex cereal on the sides instead of colors. But the most challenging puzzle in the six-sided genre seemed to be the five-by-five-by-five cube, one of only 20,000 specimens ever made.

For those who portend to have mathematical minds, this cube has about 1,213,783,704,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000,000,000,000,000,00 0,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000,000,000,000,000,00 0,000,000,000,000,000,000,000 combinations.

But only one solution.

There are also puzzles paying tribute to every regular polyhedron-pyramids, octahedrons, dodecahedrons, and those immortal icosahedrons, and all of them were in a blazing rainbow of colors.

Puzzles have been around for centuries, and they have obsessional properties, judging by the number of people participating in the hands-on exhibits on a recent day.

Some were busily trying to remove a wiffle ball from a knotted string, others building ducks from tangram "furniture," others diligently working on all 336 combinations of the six-piece burr puzzle, and others intricately involved with the implications of the geometric money puzzle.

"It's like any challenge: it's so easy to pick up [that] it's addicting," Gray says.