This study of castles and castle building ties in particularly well with a study of the Norman Conquest, the Cathars and / or Medieval Cathedral Building.
Castles: Defence and Attack! [Interactive]
A game of strategy: Spend your budget on your choice of features, then read a story of how your castle fares when faced with attack! Complete with a worksheet and extension activities. There's even a live 'leaderboard' to check the progress of your students!
A worksheet to accompany an 18-minute video, with a link to an online version of the documentary. Ideal as a homework or an extension activity (or as a quiet lesson for the teacher!).
Castles - Quizzes [Interactive]
The following quizzes are a good way of testing factual knowledge after students have finished the simulation above.