Encourage the culture vulture in your kids this weekend—for free—thanks to Smithsonian Magazine's Museum Day.  Go to the magazine's site to download and print out passes that will get you and your guests free admission to hundreds of museums and cultural venues nationwide on Saturday, September 27.  There's a location to please just about everyone:  from all of the Smithsonian offerings  in D.C., to Boston's Museum of Science, the Children's Museum of Houston, San Francisco's Exploratorium and hundreds in-between. One pass equals admission for two people; details are on the site.