Longmont, CO, Museum hosted a lowrider car and culture exhibit and I got to see it! Though small, they managed to present some prime car specimens which displayed the artwork and culture of the Mexican lowrider culture to advantage. Check out my photos!
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.