Urban Park Rangers in Inwood Hill Park. Rolling admission

http://www.nycgovparks.org/programs/rangers/conservation-corps  

The Ranger Conservation Corps

The Ranger Conservation Corps (RCC) is an urban environmental internship for high school students. RCC participants work on environmental restoration in Forever Wild sites located in our flagship parks. There are two RCC sessions each year (fall and spring), and each session lasts a total of 10 weeks. The program is offered every school day afternoon from 4-6 p.m. Students attend one day a week. There are openings for 900 students each year.
RCC participants receive community service hours, and the experience looks great on a college application. They also go on exciting field trips, such as trips on the Clearwater Sloop.
For more information, call 311 (or 212-NEW-YORK outside of NYC) and ask for the Urban Park Rangers.