1066 the game
http://www.channel4.com/history/microsites/0-9/1066/game/index.html

Build an Arch
http://www.bbc.co.uk/history/british/launch_ani_build_arch.shtml

Jousting
http://www.learn4good.com/games/action/knightgame.htm

Destroy the Castle
http://www.medievalgameplay.com/play-castle-clout.html