In a modern world where historic buildings are demolished daily to make room for hip new watergun stores, museums are more important than ever. Today’s Groupon gets tenacious time-travelers and dedicated diorama builders a $3 admission to the historic Campbell House Museum, a $6 value. The first house in the elegant Lucas Place neighborhood, Campbell House was the home of influential fur trader and entrepreneur Robert Campbell. After a recent five-year-long restoration to the tune of $3 million Earth dollars, Campbell House is one of the most accurately restored 19th-century buildings in America and home to the period paintings, furniture, light fixtures, clothing, old-fashioned LaserDisc player, and the correspondence of its previous tenants. Residue: Haunted houses, especially those that have been neglected for a long time, tend to accumulate a powdery "ghost residue," which compounds in layers on shelves, the tops of books, furniture and pottery, and even floats freely in the air, illuminated by an afternoon sunbeam. While many write this off as dust, this explanation does not account for its preternatural taste.