After a seemingly endless winter, Muscovites will no doubt be heartened by the approach of summer, with its slower pace of life, sultry days and long dacha weekends. But for parents of small children, the impending last day of school begs that perennial question: What to do with the kids?Until recently, the lack of activities for children and the restriction and costliness of many existing ones prompted many expatriate families simply to go abroad. But as the number of foreign families in Moscow grows, several groups are stepping in to fill the summer camp void.The programs on offer include both a full-time day camp and individual classes, and cater to most age groups, budgets and schedules.One new option is the Play School Moscow Summer Camp at 87A Leninsky Prospekt. The camp, for children between the ages of 4 1/4 and 6 1/2, is being organized by Chris Edstein, an Australian who previously worked for Qantas Airlines before heading to Moscow to be near her diplomat parents.The camp will occupy the same space as a preschool she founded, which closes for vacation June 24, and will operate five days a week from 9:30 A.M. to 2:30 P.M. The camp will be broken into four two-week sessions from July 4 to Aug. 26, Edstein said.Inside the renovated classrooms of the detsky sad that houses the camp is a cozy child-sized environment, complete with painting easels, puzzles, games, and small tables, where campers can work on a variety of arts and crafts, including painting and mask-making. In the back of the premises is a tree-lined yard large enough for the obstacle course and relay races that are already planned for the summer session. In addition, each session will include either an excursion to a dacha or swimming, as well as a field trip to venues such as the McDonalds factory.Edstein, who founded her daycare center shortly after she arrived 2 1/2 years ago, said she developed the summer camp in response to the demands of many of her year-round parents. "I just got inundated with people saying, where are we going to send our kids?"Parents can choose one or more of the scheduled two-week sessions, depending on availability. Edstein said that there are approximately 24 places for each session, and the cost per session will be $300 per child, including a non-refundable deposit of $50. Children are expected to bring their own lunch.According to Edstein, the camp will be staffed by experienced counsellors and headed by a coordinator with a master's degree in education. For further information, call Karen Serbin at 271-9539 or Edstein at 134-2006.Families with slightly older children may want to consider Park Place's After School Activities Program at 113 Leninsky Prospekt, which will be continuing its regular Tuesday through Thursday activities even after school recesses.The program is scheduled from 4 P.M. to 5:30 P.M. each day, although there are tentative plans to extend its hours, said Olya Bychkova, Park Place's educational coordinator. Children must be aged 5 or older, she said.Activities include chess and draughts, calisthenics, cooking, karate, dance and tennis, she said. There are two activities scheduled for each day, each one costing $30 for four classes plus the cost of materials or equipment in the case of cooking and tennis classes. Taxes are an additional 23 percent of the total price. For information, call Bychkova at 956-5272.For an option that is easier on the family budget, plan a visit to the children's village at Sokolniki Park. In Soviet years, children's programs used to be a regular feature at many large city parks, and Sokolniki's was one of the best organized. While most of those have since fallen by the wayside, Sokolniki still plans a few activities for neighborhood children, and the dinosaur park is always worth a visit. The park can be reached at 268-5951.In addition to the camp programs, there are also part-time activities for children with more specialized interests. Tennis enthusiasts, both amateurs and those with more experience, might want to take advantage of lessons. For groups of four or more, trainer Mikhail Novak gives lessons at the sports complex at 25 Ulitsa Gashenka Yaroslava for $28 per person per month on the basis of two classes a week. Individual instruction is given on the basis of $8 per one-hour lesson. For further information, contact Mikhail Novak, director and trainer, at 258-9512.Those who prefer outdoor activities might want to try the Bitsa Horseback Riding Complex, at 35 Balaklavsky Pereulok, which offers riding lessons at a variety of levels, daily throughout the summer at the rate of $10 an hour for a group of three children or more, and $15 an hour for one or two children. Children under the age of 6 will only be taught basic riding. Call Marina Velikanova at 318-6518 for details.