For the Morpurgo fans who have read 'The best Christmas present in the world', there is a lovely film about the truce on Xmas eve and day in 1914. It is Joyeux Noel [DVD] Starring Gary Lewis, Diane Kruger, Daniel Bruhl, and Benno Furmann (DVD - 2006)
Ok, purists would say that there are some historical blunders (for example, there were not yet any Scottish recruits on the Front in Dec 1914 as they were still getting trained)... see the comments on amazon for more examples...
But this is really a deeply moving and uplifting piece. Just be aware of the classification 12
(my 9 years old DS is OK with it, as we have read a lot about WWI since the 11th of November).
Moreover, this film is quite good for secondary school children learning French or German as there is a cast of Scottish, German and French actors, all speaking their own language (don't worry, there are subtitles in English).