This Saturday, it’s “It’s My Park! Day” at Prospect Park. Per an email from the Prospect Park Alliance:

Take ownership of your Park! Join us for a day of cleaning and greening one of New York’s most magnificent public parks! Meet at the Parkside and Ocean Avenue entrance to Prospect Park. The cleanup —which is part of a citywide park beautification effort—runs from 10 a.m. – 2 p.m. Registration begins at 9:30 a.m. Spend a day making the Park you love look even better. Join a great group of enthusiastic volunteers who will be sprucing up around the playgrounds, painting the wrought iron fence, and cleaning along paths. Groups of 10 or more must register in advance. People of all ages and abilities, individuals, and groups are welcome. Students can receive community service credit for participating.

For more info, email volunteers@prospectpark.org. There are events Saturday in a lot of local parks and playgrounds.