The dog days of summer are a great time to learn something new or rediscover the city without the high-season crowds.

City-wide

The 17th Annual New York International Fringe Festival
The New York International Fringe Festival (FringeNYC) is the largest multi-arts festival in North America with more than 200 companies performing for 16 days in more than 20 venues. In addition to 1200 incredible performances, FringeNYC offers extracurricular events like FringeU (Panel Discussions) FringeJR (family-oriented productions), FringeHIGH (provocative plays for teens) and more.
August 9-25
See site for venues, dates and ticket information

Fort Greene, Chelsea

Citi Bike Street Skills Class
Citi Bike partners with Bike New York to offer free classes every Thursday to help you brush up on your urban cycling skills. Attend a free Citi Bike Street Skills class to learn how the new bike share system works and to pick up all the skills and tips necessary to have a fun, safe ride in NYC. Short indoor classes are held weekly at neighborhood bike shops. Every participant will leave with a free 24-hour pass to Citi Bike, worth $9.95!
Thursday, August 8, 7pm: Red Lantern Bicycles, 345 Myrtle Avenue, Fort Greene, Brooklyn
Thursday, August 15, 8pm: Bicycle Habitat, 228 7th Avenue Chelsea
$Free

Chelsea

Stargazing on the Highline
Gaze at the stars, planets, and Moon through the high-powered telescopes of the Amateur Astronomers Association and chat with the experts about the sights you see.
Tuesdays between April 2 and October 29, beginning at dusk,
On the High Line between West 13th and West 14th Streets.
$Free

West Village

Summer Sparks Pop-up Classes
These free, professionally taught one-of-a-kind pop-up classes happen every Tuesday at Hudson River Park’s Pier 63. Coming up: Improv Outside: At this special outdoor intro to improv class, you'll learn the foundation principles of improv for beginners. The class will focus on the basics of comedic improvisation.
Tuesday, August 6th, 7 PM
Hudson River Park, Pier 63
$Free

Lincoln Center, Fort Greene

Steampunk Week
Every subculture has its celebrations, and if you’re into all things Victorian, steam-powered and Jules Verne-esque, this is one of yours, though revelers of any stripe will enjoy the weekend whirl of costume parties and gypsy marching bands, kicked off by punk cabaret rock star Amanda Palmer in a free outdoor show at Lincoln Center Out of Doors and capped off by a steampunk cruise on a Mississippi-style paddle boat.
Friday, August 9 through Sunday, August 11; see site for event descriptions and ticket prices

Harlem

Harlem Week
Harlem Week is a series of events throughout the summer that bring together all age groups and cultures to celebrate the unique essence of Harlem with over 100 events throughout the months of July and August, attracting attendees from all over New York and the world. Upcoming events include Uptown Fridays at the Studio Museum, a Dance Theater family street festival, NY Senior Citizens Day, Jazzmobile and more.
See site for events, venues and times.