Scary monsters on Hamilton Terrace. Take your pick of spooky Halloween events on Friday, celebrate Dia de los Muertos at El Museo on Saturday, cheer on NYC marathon runners on Sunday—plus more fun things to do this weekend in Harlem and beyond. Trick or Streets  in Upper Manhattan (listed from south to north) • Friday, October 31 3pm-6pm   East Harlem, E 112th St and Park Ave • Friday, October 31 3pm-8pm   Central Harlem, St.Nicholas Ave between W 116th and W 118th Sts • Frid