Castle sticks his hand inside a stone statue and pretends that something is hurting his hand.
Castle lifts a valuable treasure which triggers a trap in the crypt.
Castle engages in a sword fight with Kenny, warning him beforehand that he was very good at it, a sly reference to star Nathan Fillion's experience with swordplay in his role in the series Firefly.
Mentioned by several characters.
When the Da Vinci Code novel is referenced, Castle remarks, "Just like Tom Hanks in the movie."