A new movie is in production about the Knights Templar. Ironclad is being directed by Jonathan English and is based on the very real story of England's Rochester Castle. From the Internet Movie Database listing:
It is the year 1215 and the rebel barons of England have forced their despised King John to put his royal seal to the Magna Carta, a noble, seminal document that upheld the rights of free-men. Yet within months of pledging himself to the great charter, the King reneged on his word and assembled a mercenary army on the south coast of England with the intention of bringing the barons and the country back under his tyrannical rule. Barring his way stood the mighty Rochester castle, a place that would become the symbol of the rebel's momentous struggle for justice and freedom.
The film is rumored to star Megan Fox, Paul Giamatti, Robert Carlyle, Bob Hoskins and Richard Attenborough. It is due in theaters in December 2009.