Have students work together to build cardboard castles in order to understand the elements of castle construction. You can have each group work to build a famous castle, like Stirling Castle, Windsor Castle, or The Tower of London, or let students design their own castle.
Make a list of materials so that each castle is built with the same supplies. Some cheap and abundant resources for castle construction include empty cereal boxes, white glue, empty tissue boxes, paper towel tubes, egg cartons, and paint.
Students can use castle features such as turrets, towers and a drawbridge in their construction. Have each group present its castle and explain its features.
Create a reading list about castles and the medieval lifestyle for your students, and have each student make a presentation to the class. Decorate your teacher's chair like a throne, using a faux fur or crushed velvet throw rug. Make a construction paper crown or buy one at a party supply store. Have each student wear the crown and sit on the throne to present her project.
After giving your students a lesson on medieval and castle vocabulary and terms, assign them a crossword puzzle and/or word search with your terms. Word games re-enforce the words and their meanings. You can make your own word puzzles for free on some websites and you can also find free pre-made word puzzles. See the Resources section. After grading the word puzzles, put crown stickers on the high-scoring papers.
Teach your students how to play chess. Chess became a widely popular game in the Middle Ages, and each game piece represents a part of medieval life: castles, king, queen, bishops, knights, and pawns. You can create a lesson about each piece and then invite students to play.