ONE of Maine's most popular country fairs prides itself on what itdoesn't have: No Ferris wheels or fried dough. No cotton candy or midway rides. No chance to lose money on the ring toss or shooting gallery arcade games.Instead, there's "natural" soda and pig-calling contests, organic corn on the cob, maple-syrup frappes, and manure pitch-offs. That may wrinkle the noses of the uninitiated, but a record crowd of 60,000 streamed into the village of Windsor two weeks ago for the 15th Annual Common Ground Organic Fair. Chemical-free fun never looked so good. Besides being entertained, fairgoers learned how to compost, grow organic vegetables, or build a log home. They wandered through long sheds full of organic grain-fed cows and "free range" chickens. And when they were done eating their whole-wheat strawberry cream puffs, they dropped the trash into designated recycling bins. The fair is "helping people to live more self-sufficiently, more in harmony with the natural world, and more as part of a caring community," says Nancy Ross, executive director of the Maine Organic Farmers and Growers Association, which sponsors the event.