Cheyenne Mountain Zoo will feel the Halloween spirit when thousands of little ghouls and goblins attend Boo at the Zoo, resuming with its remaining four nights on Friday , Oct. 25, 2019. The event is a fun way for families to trick-or-treat and enjoy Halloween festivities in a safe and unique environment. This year’s Boo at the Zoo started Oct. 18 – 20 , and resumes on Oct. 25 – 27 and 31. Boo hours are 4 to 8:30 p.m., with the last admission at 7:30 p.m. The Zoo will close for daytime admission on Boo nights at 3 p.m., with the last admission at 2 p.m.