Harlem's week runs from a science-themed Halloween afternoon to a 1970s dance party, and every item on this list is free. All four come from NYC Parks and the community groups that run programs in Harlem's parks and recreation centers.

Friday, Oct. 30: Haunted Heights in Morningside Park

NYC Parks, the Friends of Morningside Park, and two Columbia University groups, the Columbia University Space Initiative and the Zuckerman Institute, are throwing a Halloween afternoon on the park's North Lawn. The program includes music, arts and crafts, kids making their own lava lamps, and a chance to see and interact with human and animal brains. Costumes are encouraged.

When and where: Friday, October 30, 3 to 6 p.m., at the picnic oval on the North Lawn, inside the park at West 120th Street and Morningside Avenue. Free. Take the A, B, C or D to 125th Street or the 2 or 3 to 116th Street.

Saturday, Oct. 31: The first Trick or Treat Fest at Abyssinian Tot Lot

The volunteers who run Abyssinian Tot Lot, the small park on West 139th Street between Adam Clayton Powell Jr. Boulevard and Lenox Avenue, are holding their first annual Trick or Treat Fest. The organizers describe it as a safe spot for kids and their parents to trick-or-treat, with candy stations and game stations, open to the whole neighborhood. The tot lot takes its name from the Abyssinian Baptist Church, the first African American Baptist congregation in New York State, founded in 1808.

When and where: Saturday, October 31, 3 to 6 p.m., Abyssinian Tot Lot, West 139th Street between Adam Clayton Powell Jr. Boulevard and Lenox Avenue. Free. Take the 2 or 3 to 135th Street.

Monday, Nov. 2: Harlem Run's Monday Night Run

Harlem Run leads free, pacer-led runs and walks through the neighborhood every Monday night, taking a different route each week and starting and finishing at Marcus Garvey Park. Pace groups run from 7-minute miles to 12-minute miles, with run-walk and walking groups as well, and the group says it is open to all ages and abilities. There is a bag drop, though space is not guaranteed.

When and where: Monday, November 2, 6:45 to 8:30 p.m. Meet between the public restroom building and the baseball field on the south side of the Pelham Fritz Recreation Center, at West 122nd Street and Mount Morris Park West. Free; registration recommended but not required. The run repeats every Monday through June 2027.

Friday, Nov. 6: A '70s silent disco at Pelham Fritz

The Pelham Fritz Recreation Center is opening the holiday season with its fourth silent disco, and this one has a 1970s theme. Guests dance to music on wireless headphones, and the center asks people to come dressed in vintage 1970s clothes, or in fun clothes from any era.

When and where: Friday, November 6, 5 to 8 p.m., Multi-Use Room B, Pelham Fritz Recreation Center, 18 Mount Morris Park West. Free and open to the public; RSVP by emailing Lasharn.Cooper@parks.nyc.gov, with registration open through November 5. Take the 2 or 3 to 125th Street.

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