The healing hot springs at Glenwood Springs, Colorado, in the Rocky Mountains has been a draw for tourists and swimmers since before the first homesteader in the 1880s. In addition to the spa resorts, it offers history such as Doc Holliday, wonderful restaurants, historic hotels and even an altitudinous amusement park! Just a few hours west of Denver by car or Amtrak, it makes a great weekend destination.
The Museum of Fine Art in St. Petersburg, Florida, is small but impressive. I've visited it more or less regularly for years, and they present quality exhibitions in a professional environment. A 2006 expansion allows the museum to offer a cafe and respectable gift shop, in addition to their permanent collection and revolving exhibits. It's a fine way to spend an afternoon, especially if you include the nearby Dali Museum in your itinerary.