Yes, part of the movie, National Treasure 2, was filmed in and around Mount Vernon. And we got to see the basement area of Mount Vernon where it took place, plus saw photographs of the fancy party that Nicholas Cage crashed to talk to the President of the USA, and saw the place Nicholas Cage came out of the Potomac River, removed his wet suit, and appeared in formal evening clothing -- perfectly dry. (it's impossibile for clothing to be dry under a WET suit, but often used in movies)
The two grandkids were surprised to discover that all parts of the visit were interesting, even the history parts. The boat ride on the Potomac and the ice cream at the end helped.
They each took home a souvenier -- a key on a necklace to match the key to the Bastille that Lafayette gave George Washington. (a little bit of French history there, as well)