PBS created an hour long special based on the Castle book and I recently purchased a DVD version from Amazon. I remember I first watched this in Junior High, my friend and I did a presentation on castles in class and had watched this on a clunky old VHS player to learn more about the subject.
The video transfer to DVD is pretty bad, the image is fuzzy and is showing its age. Castle is sixty minutes long and is narrated by the author, he gives a tour of a 13th century Welsh castle describing all of the architectural features and defenses. This is inter-cut with an animated story of Aberwyvern Castle which shows the construction process, what life was like in the middle ages and the the castle in action defending against Welsh raiders. Its all very wonderfully done and reignited my love of all things medieval.
PBS also turned several of the other Macaulay books into television special, I have not seen the others but intend to seek them out. If your interested you can pick up Castle the book and video from Amazon, links below!
Castle at Amazon
Castle DVD on Amazon