During Star Wars Celebration III, VFX Supervisor John Knoll became an honorary member of the 501st Legion, a not-for-profit and probably biggest Star Wars costuming club, which usually does quite a bit of charity and volunteer work.
Here is the announcement from Dean Plantamura, of the Florida Garrison:
On April 23rd, 2005, the 501st Legion of Stormtroopers inducted John Knoll into their ranks as an Honorary Member and presented him with a plaque thanking him for his contributions to the Star Wars legacy. The presentation took place at the end of Saturday's visual effects panel in the Sagamore Ballroom at Celebration 3 and the audience was treated to a surprise appearance of Darth Vader and a squad of Stormtroopers.
Thanks to Dean for the news.