In Nashville we have this beautiful place called Cheekwood Botanical Garden and Museum of Art. I would say it's a well-kept secret, but I think the word's gotten out over the years, much in part to some cool and unique exhibits that they bring in. They make such good use of the whole grounds and gardens, as well as the interior of the mansion, where the art museum is housed.
This year's outdoor/indoor exhibit is called "LIGHT," by British artist Bruce Munro. I'll let you read about it here. The professional photos on the site are much better quality, but I took some of my own the two times I have gone so far and got a few that I was pleased with.
Both times I went with friends and we had a great time walking around seeing the lights and enjoying the summer nights. The exhibit will run through November 10, so if you haven't seen it, I highly recommend it!