Do you have anything to declare? Yes, moon dust and moon rock. This is the customs form filed by NASA for the astronauts entering Honolulu after departing from the moon. The Atlantic recently posted it but Space.com has the full story in this 2008 article. Apparently, it was done more as a fun ritual than any governmental requirement. Still, a fascinating artifact! "Back from the Moon, Apollo Astronauts Had to Go Through Customs"