Bay seniors on the hunt for paranormal activity might want to check out the Chinatown Ghost Tours. Chinese culture is rich with magical spirits. These walkthroughs of back alleys occur on Fridays and Saturdays from 7:30 to 9:30 pm. They can’t promise any actual ghosts but there are fascinating stories of the gang violence, prostitution, rampant murders and opium dens that marked the early history of Chinatown. Adults $29. Very mixed reactions on Yelp.