A nice mini-park near Glen Park Rec Center that is worth exploring if you're in the area. The park can be accessed either from Joost or Mangels; it is roughly halfway between Congo (to the west) and Baden (to the east).
Joost/Baden Mini Park is owned by the San Francisco Recreation and Park Department.
23-Monterey or 36-Teresita
Offboard at either Monterey and Congo *or* Monterey and Baden. Walk one block north on either street to Joost Ave (note: it's uphill). If you're on Congo, make a right; if on Joost, head to the left. The park is halfway between the two streets, on the north side.