For a month, a haunted house billed as one of the scariest in New England will be open on weekend nights, with a portion of the proceeds benefiting Cops for Kids with Cancer, a charity that provides money to families with children diagnosed with cancer. The Hidden Hotel, located at 95 Washington St., will be open on Friday, Saturday, and Sunday nights from 6 p.m. to 10 p.m. until Oct. 27. Tickets cost $18. Visit www.thehiddenhotel.com for a complete list of dates, times, and a coupon for $3 off each ticket.