CYCLING

July 28: Bike Maintenance Basics, College Park REI, 7 p.m. REI hosts this free introductory class to teach new cyclists how to take care of your bike. These classes fill up quickly. Info: rei.com.

HIKING

July 23: Moonlight Hike, C&O Canal, Great Falls, Md., 8:30 p.m. The Capital Hiking Club leads this 4-mile hike along the C&O Canal from Old Angler's Inn. Info: capitalhikingclub.org.

MOUNTAIN BIKING

July 25: Cranky Monkey, Annandale, 8 a.m. The race in Wakefield Park consists of a 6-mile single and double track loop over moderate terrain. Bikers will compete in classes, based on age and experience level. Info: ex2adventures.com.

RUNNING

July 24: Crystal City Twilighter 5k, Crystal City, 8 p.m. This evening race follows a flat course around Crystal City with an after-party. Info: crystalcitytwilighter.com.

July 25: Riley's Rumble Half Marathon, Boyds, 8 a.m. The race is an out-and-back through the hills of northern, rural Montgomery County. Info: mcrrc.org.

TRIATHLON

July 22, 25: Tri It Now Triathlon Clinic, Level 2, Manassas. This is a workshop-style clinic for triathletes who have competed in several triathlons. It will include training and racing guidance from professional coaches. Info: triitnow.com.

July 25: Rockettes Landing Triathlon, Richmond, 7 a.m. This triathlon (1.5k river swim, 40k bike, 10k run) offers plenty of categories: aquabike (swim/bike), aquathlon (swim/run) duathlon (run/bike/run), and relays. Info: rockettslandingtri.racesonline.com.

Aug. 8: Splash 'n Dash, Silver Spring, 7:30 a.m. Competitors will do a 300-meter pool swim at Martin Luther King Jr. Swim Center in White Oak, followed by a 5k run through the adjoining park and trail. Info: capitalsprints.com.