My friend did a knights and castles topic a couple of years ago and her classroom looked amazing. She had a drawbridge going into the room which I think was made of that sticky wood look laminate stuff so the kids could walk over it without it ripping. She made paper chains attaching it to the door. Inside she turned the blackboard into a giant fireplace and she made banners from material to hang from the ceiling. She also used hoop to make a candle chandelier. I think she just did these herself to create the setting and then the children made other things as part of the topic such as making their own coat of arms. A few of the activities she did included having a medieval feast and her husband came in dressed up as a knight. After doing lots of work on castles the children made castles at home with their parents and brought them in. They then had an open afternoon in the class where other classes came to look at their castles and they explained how they made them and told the visitors all about medieval castles. I can find out about the other activities she did if you need anymore ideas. Have fun!