Man. I absolutely love these guys for doing this. The moment where the two little kids are shown made me so happy to think about the magic those two must have been feeling, seeing Darth Vader and Princess Leia in real life. They may be old enough to understand that it is not real, but the thought made me happy nonetheless.
If you have not already experienced the joy of Improv Everywhere, go spend an hour or two on their website. It is wonderful.
Here they re-enact the opening scene from Star Wars: A New Hope.
In this one they re-enact the library scene from Ghostbusters.