Nearly half of everything worth doing can be done in bed, if you don't count trout fishing. You can read in bed, talk, eat and drink, watch TV and listen to music. You can play gin, play scrabble, play dead and, since you already have someone over for cards, you can play around. You and a friend can kneel at opposite ends of the counterpane and play a very languid version of Ping-Pong: use the pillows for a net, and keep the cat out of the room or he'll swat at the ball. Remember, you spend over one-third of your life in bed, and it's the good third. Indeed, no chapter in the history of furniture is more inspiring than the story of the bed, although the section on floor lamps does have a few juicy bits. BEDS OF THE PROTOHUMANS Archeological evidence suggests that our prehistoric forebears slept upon vegetables -- probably on cucumbers and zucchini. They gradually progressed through shrubbery and itchy leaves to the well-known beds of straw of the neolithic period. The cave dwellers devoted centuries of attention to improving the pillow. Paleolithic sleepers commonly rested their heads upon rocks, to nobody's great satisfaction. In those days, a pillow fight was often a fatal encounter. Furthermore, it was nearly impossible to imitate a fat person by stuffing a pillow in your pants: the rock could slip down your leg and break your feet. With the domestication of animals came the first real pillow progress. However, attempts to coax pigs and dogs to lie under someone's head all night met with little success. The protohumans grew eager to domesticate the chicken or at least get one a first-name basis. Alas, the chicken had a tendency to roll around, to walk in its sleep and to snore. Ane no one enjoyed waking with an egg up his nose. It was the radical concept of plucking that ultimately produced the crude ancestor of the modern pillow, a source of bliss to the cave people, even if the chickens weren't wild about the idea. THE DARK AGES Kept in the dark for centuries, people spent a lot of time thinking about beds. With the rise of monarchy came the king-size bed, the queen-size bed and several forms no longer extant, including the count-, duke- and baron-size beds. However, the medieval character was generally unreceptive to innovation. The creator of the first convertible bed was burned at the stake, and his bed was denounced as an affront to the nobility, representing as it did the symbolic doubling over and goosing of the queen. Late in the middle ages, in the ghetto of Prague, a group of Talmudic scholars formed the theories that would untimately lad to foam rubber, but the brutality and ignorance of that age prevented its immediate producion. Indeed, it was not until the Renaisance, with the opening of the spice trade, that our ancestors had a clue about black satin sheets. THE INDUSTRIAL REVOLUTION The 19th century brought renewed ingenuity to bed technology. This was an age of experimentation with the cast-iron bed, the steam bed and mechanical quilts. Thomas Edison applied for a patent for his electric bed, a device intended for the humane execution of sleeping convicts, later to evolve into the electric sofa, the electric love seat and the device we know today: magic fingers. In addition, it was in this era that Ransom Olds became the first person to sleep in a car. MODERN TIMES Our own century has focused on special-purpose beds, including the sleeping bag for campers, the cot for soldiers, the Murphy bed for people from Dublin and the bed of roses for weary horticulturists. The last decade brought forth the water bed for adult sleeping, along with its children's version: the wa-wa bed. And the future holds even greater promise as NASA research teams explore the low-gravity bed, destined to be the first mattress on Venus. We've come a long way from horse-hair ticking. A FEW BED FACTS

General Sherman worked out many of his battle plans by forming his sheets into a topographic map of Georgia.

In the first known example of pillow talk, a bolster in Philadelphia said "Pipe down you guys, or I call the cops!"

In 14th-century Bavaria, hogging the covers was a capital crime.

In 1305, a group of conspirators surrounding King Phillip of France threatened to short-sheet the Pope unless the papal court were relocated in Avignon.

Catherine the Great is known to have died in bed, but contrary to rumor no horse was involved. Court records indicate she was playing with electric trains and citrus fruit.

Beds of many lands: In the mountain villages of Peru, many native Indians sleep with their socks on.

In one of the first confirmed cases of tool use among animals, otters around Vancouver were found to be constructing tiny bunk beds.