Here’s a round-up of Halloween events to add to your calendar. Mark Twain House, Graveyard Shift Ghost Tour, Hartford, thru December Pumpkin Patch at the Connecticut Trolley Museum, East Windsor, Select Days in October Downtown Mystic Ghost Stroll, Mystic, thru November Nature’s Art Village, Montville Center, every Friday, Saturday & Sunday in October Mystic Seaport: Trick or Treat, Mystic, 10/31 Scarecrow Fest, Old Saybrook, 10/16 – 10/31 Sherlock Holmes and the Haunted Cabaret, Bridgeport, 10/5 – 11/3