I saw the National Symphony Orchestra play a couple tunes as part of a massive free concert on the back lawn (west side) of the US Capitol building a couple months back. They played a compilation of a few different star wars songs (along with many others, totally un-related) Between the setting and the music, I was more or less in tears.
Then I realized it was just the rain, which quickly intensified and left me heading for a metro station.
I know they do LOTR in concert at the Wolfpack not to far from DC, which I intend on checking out. I would love to see Star Wars as well. Enjoy!