I'd vote for the Challenge also - good call! And the famous Japanese actor Toshiro Mifune co-starred in the Challenge. ( eg
http://www.youtube.com/watch?v=1mgD8q3I7nc )
(While not concerned with aikido, you may also want to look up Toshiro Mifune as a samurai in the western Red Sun with Charles Bronson, famous French actor Alain Delon):
http://www.youtube.com/watch?v=I193V0XC0n4 ).