Drop-in tai chi Student-led sessions. Fridays, 9:15 a.m. Friendship Heights Village Center, 4433 S. Park Ave., Chevy Chase. 301-656-2797. www.friendshipheightsmd.gov. $3; registration required.

Beginning recreational kayaking For age 12 and older, instructors from the American Canoe Association teach basic strokes and boat control. Participants must be able to swim. Equipment provided. Saturday, 9:30-11:30 a.m. Black Hill Regional Park, 20926 Lake Ridge Dr., Boyds. 301-528-3492. www.montgomeryparks.org/ . $16. Registration required.

Guided bike ride Along the Carl Henn Millenium Trail, an 11-mile bicycle beltway around Rockville. Sponsored by Rockville’s Bicycle Advisory Committee. Sunday, 10 a.m.-noon. Lincoln Park Community Recreation Center, 357 Frederick Ave., Rockville. 240-314-8780 or www.facebook.com/bikerockville. Free.

AARP safe driving class For age 55 and older, focusing on defensive driving. Monday, 10 a.m.-3 p.m. Margaret Schweinhaut Senior Center, 1000 Forest Glen Rd., Silver Spring. 240-777-8086. $12, registration required.

Damascus Library bloodmobile Donations can be made Monday, 3-7 p.m. Registration required. Visit the Web site, click on “Schedule a Donation,” then “Donate Blood” and use Sponsor Code 7581, or call 866-256-6372. Damascus Library, 9701 Main St., Damascus. inova.org/donateblood.

Prostate cancer support group For anyone affected by prostate cancer. Monday at 7 p.m. Suburban Hospital, 8600 Old Georgetown Rd., Bethesda. 301-896-3939. Free.

Free blood pressure screenings Sponsored by Holy Cross Hospital. Tuesday at 12:30 p.m. Margaret Schweinhaut Senior Center, 1000 Forest Glen Rd., Silver Spring. Register at 240-777-8086.

Breast-feeding support group For pregnant and breast-feeding women. Babies welcome. Sponsored by Breastfeeding USA. Tuesday at 6 p.m. Holy Cross Hospital Resource Center, 9805 Dameron Dr., Silver Spring. 301-326-4715. Free.

Froggy Hollow trail hike For fitness enthusiasts 18 and older, a guided moderate hike through a mature forest and creek valley, with steep climbs. Wednesday, 9:30-11:30 a.m. Little Bennett Regional Park, 23701 Frederick Rd., Clarksburg. 301-528-3492. www.parkpass.org. Free, registration required.

Square dancing and lessons New dancers welcome; casual dress. Wednesday at 7 p.m. North Chevy Chase Christian Church, 8814 Kensington Pkwy., Chevy Chase. 301-587-5861. www.gerrymanders.net. $6.

— Compiled by Lisa M. Bolton

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