The earliest proto-fork was used by the ancient Egyptians, who worshipped it as a deity. Of course, the Egyptians worshipped darn near everything, so it was no big deal. It was really nothing more than a spoon with a spike on one end and was used for removing snails from their shells. This was far more efficient than those itty-bitty little eviction notices used by the Greeks. It was also used for removing ear wax until that practice was outlawed by the Egyptian Occupational Safety and Health Administration.
The fork makes its next appearance in ancient Rome, where it was not worshipped as a deity, having lost out to the knife. By this time, it had two tines, and was used mostly for removing that last olive from the jar. It was also put to good use in roads, making travel far easier, as up to this time all roads went to only one destination. This prompted the famous orator Yogius Berrius to declare "When you get to a fork in the road, take it."
By the Middle Ages, the fork had spread to Central Europe. Except Spain, where it was denounced as a heretic and burned at the stake. Early European forks are hard to find, as they were all stolen by the Goths and Vandals when they came to dinner and stayed for a few decades. When they discovered Europe was out of forks, they burned the place and left. The only forks left behind were the extra-large ones, which were used for digging tar at the tar pits and were known as "pitch forks".
Returning eastward, the Goths and Vandals took their summer vacation in what is now Russia, where the government declared that the fork had been known to the Russian peoples for millenia, as they had originally invented it, only to have it stolen by Western imperialists.
One of the forks was also left in Poland as a gift to King Wraklav the Stupid, who declared it to be utterly useless. Of course, he was using the wrong end, so it took a while for the fork to catch on there.
The earliest settlers to the Western Hemisphere brought the fork with them to the New World, where the Pilgrims amazed the Indians with their prowess at reaching across the table and spearing that last potato on the plate. This was pronounced to be a huge "no no" by Miss Manners, punishable by three days in the stocks. Unfortunately, as adept as they were at spearing food with it, the settlers were equally inept at actually using it to eat with, nervous as they were at the prospect of being raided at any moment by bands of jealous Indians. This led to numerous embarassing dining accidents, giving rise to the Indians' observation that "White Man speak with fork in tongue". It also led to the Indians laughing their butts off after dining with White settlers. Some scholars believe that the entire Thanksgiving thing was nothing more than a ploy by the Indians to have a good laugh at the expense of the settlers.
In modern times, the fork is still put to good use, having even been taken aboard the Space Shuttle, where it was used to repair the Hubble Space Telescope by pinning the hannenframmis to the franistan. As humans venture farther out into space, the fork will no doubt be along for the ride. Perhaps it will even be left with primitive civilizations along with a cheery "May the fork be with you!".
[This was written in March '97, subsequent to having lunch with some people I worked with at Travis AFB. Someone wondered aloud where the fork originated, with got my creative juices going. With predictable results.]