KNOXVILLE – BOO! at the Zoo, Knoxville’s cherished Halloween celebration, is back for its 38th year. The event offers three weekends of spooky fun beginning Thursday, Oct. 10 to Sunday, Oct. 13, continuing Oct. 17-20, and Oct. 24-27, from 5:30 p.m. to 8:00 p.m. each night. This year’s…