Blue Planet Featuring scuba certification, reef surveyor, and divemaster courses, plus others. $95–$295. At pools throughout D.C.; main office is at 1761 S St. NW. (202) 527-9491. blueplanetdc.com.

Dumbarton House Six-week 19th century skills and etiquette course features lessons in sewing, gaming, and dancing. $12 per class, or $62 for the entire course. 2715 Q St. NW. (202) 337-2288. dumbartonhouse.org.

Gadsby’s Tavern Museum Learn the steps of George Washington and Abigail Adams with 18th-century dance classes for singles or couples. $12 per class or $30 for three. 134 N. Royal St., Alexandria. (703) 746-4242. gadsbystavern.org.

Halau O ‘Aulani Native Hawaiian School Classes in hula, ukulele, and Hawaiian language and crafts. $240 for two-month courses; $320 for three-month courses. 3700 S. Four Mile Run Dr., Arlington. (301) 919-7905. halauoaulani.org.

National Diving Center Classes in subjects like open water certification, basic first aid, underwater photography, and advanced SCUBA. $100–$399. 4932 Wisconsin Ave. NW. (202) 363-6123. dcdivers.com.

The Writer’s Center Workshops for beginner, intermediate, and advanced writers in a variety of genres including rock journalism, screenplays, fantasy, grant proposals, songwriting, and more. $40–$405. 4508 Walsh St., Bethesda. (301) 654-8664. writer.org.