Central Park volunteering (ongoing)- now that spring is unofficially here, you can get outside to volunteer with Central Park. Go to http://www.centralparknyc.org/volunteer/ to find available dates. The Central Park Conservancy offers one-time, drop-in opportunities, and ongoing positions requiring a long-term commitment.
Citymeals on Wheels (ongoing)- work in teams to bring food to homebound elderly. Many opportunities are available near Sinai! For volunteer information, go to http://www.citymeals.org/volunteer-with-us.
Volunteering with animals (ongoing)- these often require long-term, regular commitments and pre-volunteer training.
Animal Care and Control-- http://www.nycacc.org/howtovolunteer.html