Blooper

During the joust near the end of the film, the red knight's lance can be seen breaking right before it cuts to a new shot and the lance is perfectly fine.

As Calvin steps up to bat for the first time, Princess Katey can be clearly seen in a Knights jersey on second base, before Calvin travels to Camelot.

The "Big Macs" Calvin makes for the princess include tomatoes; an ingredient native to the New World and unavailable in Medieval England until the the discovery of the Americas in the 15th century.

When Calvin makes Big Macs for Princess Katey, he includes tomatoes, or "poisonous love apples", which are not a topping on the iconic McDonalds sandwich.