The Fogg Museum is the gem of the Harvard University Art Museum system. For one thing, the building itself is a work of art. Inside the stately granite facade, complete with imposing staircase and pillars, visitors are greeted at an information desk and led into the Fogg courtyard. The courtyard is an enormous open space right in the middle of the museum, extending up three stories (the museum's full height), and used for university and museum functions throughout the year. If you're lucky, you might catch Harvard college's Collegium Musicum performing (you can pick up a schedule of events at the visitors' desk).
Not only is the building fantastic, but in addition, it houses one of the most diverse and important art collections in Boston. In an intimate setting, visitors wander freely from the Mondrians on the third floor (which is mostly modern) to the European masterpieces in the first floor galleries. Somber navy-clad gaurds stand at every corner to "answer questions" - the museum may be small, but it isn't taking any chances with its art. Best of all, the Fogg Museum is open free of charge to all Harvard university affiliates, and, for a nominal fee, to everyone else as well.