WHEN a big circus tent went up a year ago on an empty lot bordered by a noisy expressway and a favela, the residents didn't think twice. They quickly stole the circus's wooden benches to improve their shacks.But today there are benches under the big top, ready to be filled with an audience that will help local child performers celebrate the Vila Prudente circus school's first year of life. "We had to educate the community about who we are," says Marisa Martins Marques, the school's director and a psychologist. "Now we have just one night watchman for this whole big area, and nothing has ever happened again." This circus school, one of eight in Sao Paulo, is part of a state-run program serving 24,000 children. The teachers are retired or weekend circus performers. Begun in 1988, the program was one of 10 worldwide singled out for distinction by UNICEF in 1990. Several performers have won prizes at an international circus competition held annually in Monaco. Practicing for the anniversary show, a barefoot 13-year-old girl wearing a New Kids on the Block hat says it took four months to get the hang of the lasso rope she is twirling. Her words echo under the tent, where others rehearse a dance number, juggle, or jump on the trampoline. "It's fun. It's dangerous in the favela. It's better here." The half-day circus school, which includes arts and theater workshops, is funded by a state-owned electric utility. It is one of many state, municipal, and privately-run programs to help the city's millions of poor children. The state educates preschoolers and latchkey children; provides others with outdoor art sessions, job training, legal aid, and a telephone helpline; runs homes for abused children and respite houses for street children; and trains teachers to attract street kids into the programs. An estimated 50,000 children spend time on Sao Paulo's streets. Although most do have a home and some family tie, poverty forces them to seek sustenance on the street. The circus school is meant to provide another alternative. At first glance, the circus school doesn't appear to offer many practical skills. But, says Ms. Marques, it actually goes right to the heart of the matter. "The program uses artistic language as a tool to form the individual, the citizen, to improve the child's self-image, and transmit an idea of his rights and duties," she explains. Educators set up an atmosphere of respect, she says, in which children learn the limits of what they can expect from others, and what they can do for themselves. A workshop for older youths includes visits to companies, tips on paperwork and dressing, and a unit on community health and educational resources, in which the teens pass on what they learn to older residents.