what are those young men doing?

Spotted in an article on CNN about New York tourism returning to pre-9/11 levels:

For adults, "the city that never sleeps" offers such attractions as guided night walks through Central Park -- by foot or rickshaw cab -- and private jazz tours, with club-hopping into the wee hours.

...

Central Park night crawlers are advised to bring along a flashlight, said guide Eric Stein, for a tour that includes "the darkest 37 acres" of the park -- The Ramble, an almost untouched patch of Manhattan wildlife.