All the usual disclaimers apply: I don't own Castle, never will, and certainly have no chance of ever profiting from it.
Pi
Bakery boxes are scattered all over the break room.
"What'll it be, detective?" Castle asks. "Apple? Peach? Banana cream?"
Ryan and Esposito are having some of each.
"Must be March 14th." She pours her coffee.
Castle brings her a plate. "You have a thing for cherries, don't you?"
She hands it back. "Not my favorite constant."
He spears a bite. "Then what is?"
"Mu." She gives him the once-over. "It's the coefficient of friction."
The dessert rolls off of his fork and hits the floor.
The guys spend the afternoon hassling Castle about losing his cherry. She smiles every time.