Today we watched the Space Shuttle Discovery land at Dulles Airport on the back of a 747 for its final flight. It made two passes overhead, and I was well positioned for both.
Update (4/26/2012): I got a good look at Enterprise at Dulles airport today. It's all loaded up and ready to leave for its new home in New York.
Update (4/9/2012): I went to visit Discovery in her final resting place this morning. Absolutely magnificent.