Festivals around Washington have a habit of growing elaborate, with citified crafts and exotic foods. But Greenbelt's Labor Day Festival has remained just about the same for the last twenty-three years (and I can vouch for that, having been to the very first and most of them since). The piece de resistance is still the Sunday pancake and sausage breakfast, where the politicking is as thick as the syrup. The parade (10 a.m. Monday) still has the floats and clowns and antique cars and bands and decorated bicycles as it has for years, except that some of the majorettes now are the children of the originals. The carnival is as exciting as ever, so long as you are under 12. They still have contests Labor Day afternoon (3 to 6 p.m.), the likes of a diaper derby, a three-legged race, bubblegum blowing, and watermelon wating. All day there are concerts and talent shows, and tonight square dancing in the streets from 9 to 1. Monday afternoon (2:30 to 4:30) demonstrations of Americans at Work are going modern, with Moped riding among the violin making, cow-milking and carpentry exhibitions. But don't worry, the refreshments still consist of hot dogs, hamburgers, cotton candy, candy apples and popcor. No pate - yet.

Greenbelt LaborDay Festival. Greenbelt. Today, breakfast 9 a.m. to 1 p.m., $2.75 adults, $1.75 chidlren, under 3 free. Other events todays, 1 p.m. to 1 a.m., and tomorrow, 10 a.m. to 6 p.m. Free. 44-0449 or 474-5310