Rummage Sale Set To Help Hospital

The Ladies Board of the Loudoun Hospital Center will sponsor its annual rummage sale tomorrow and Saturday at the 4-H Fairgrounds near Leesburg. The sale, which will be in the barns at the fairground, features clothing, housewares and electronic and garden tools. There will be a silent auction. Call 777-3116 or 338-7207. Roundup of Volunteers

The Loudoun Volunteer Center and WAGE Radio will hold their third annual fall recruitment program for volunteers from 10 a.m. to 4 p.m. Saturday at Virginia Village Shopping Center in Leesburg.

Representatives of many of the county's 375 agencies and nonprofit service groups will answer questions. Call 777-0113. Round Dancing Event

The Loudoun Rounders, a round dance club, will host its annual open house from 4 p.m. to 6 p.m. Sunday at Douglass Community Center in Leesburg. Round dancing is a hybrid of ballroom and square dancing. Call 430-9041. Garden Club Forming

The Sterling Area Garden Club will hold its kickoff meeting at 7:30 tonight in the upstairs meeting room of Farmers and Merchants Bank at Sterling Boulevard and Davis Drive. Call 450-0639 or 450-5337. Hunt Opens Its Season

The Fairfax Hunt begins its racing season at 2 p.m. Saturday at Belmont Plantation. There will be six races. Gates open at 11 a.m. Belmont is on Route 7 about four miles east of Leesburg. Admission is $10. Children younger than 12 get in free. Call (703) 787-6673 or 777-0519. Soviet Official to Speak

The Russian Club of Leesburg will sponsor a lecture by Vladimir Zaemsky, first secretary of the Soviet Embassy, at 2 p.m. Sunday at Ida Lee Park. Zaemsky will speak about current events in the Soviet Union. The lecture is free. Call 777-1262 or 689-1420. Astronomy in the Park

Sky Meadows State Park will sponsor an astronomy program led by Geoff Chester of the Smithsonian Planetarium from 8 to 11 p.m. Saturday. The program, which will be canceled in case of rain, fog or heavy cloud cover, is free. A $1.50 parking fee is charged at the park on weekends. Call (703) 592-3556. Lions to Sell Brooms

The Leesburg Host Lions Club will hold its annual broom sale from 9 a.m. to 2 p.m. Saturday near Safeway, Giant and K-Mart and in the Virginia Village Shopping Center. Money raised helps support local charities. Call 777-5511. Basketball Kickoff

The Seneca Ridge Basketball League will hold registration for the coming season from 9 a.m. to noon Saturday and on Sept. 29 at the Sugarland Run Community Center, Sterling. To be eligible, a student must be enrolled at Seneca Ridge Middle School, or in an elementary school -- Algonkian, Meadowland, Sugarland, Ashburn or Sterling -- from which Seneca Ridge draws students. The fee is $25 per player or $35 per family. Call 450-4208. Course in Publishing

The Loudoun campus of the Northern Virginia Community College will sponsor a special course on desktop publishing for beginners, intermediate students and advanced students. The beginning course for publishing on a personal computer is Saturday, followed by an intermediate course Sept. 29 and an advanced course Oct. 20. The beginning course for publishing on a Macintosh computer is Nov. 3, an intermediate course Nov. 10 and an advanced course Nov. 17. Classes will be 9 a.m. to 4 p.m. Each session is $85. Call 450-2513.