Lots of free activities in the parks across the city this weekend….. Saturday, December 15 Volunteer Cleanup at Kaiser Parkat Kaiser Park Parkhouse, Brooklyn9:00 a.m.–2:00 p.m. Volunteer Cleanup at Rockaway Beachat Beach 32 & the Boardwalk, Queens10:00 a.m.–1:00 p.m. Photography: Landscapesat Astoria Park, Queens11:00 a.m. 9th Annual Family Holiday Craft Workshopat Greenbelt Nature Center,…