Out of the mouth of...........teenagers

Cody: "My friend ruptured his ACL and is stuck inside all summer!"
Me: "That's not a fun way to spend the summer.  How did he do that?"
Cody: "He's had problems with his knees before and he plays baseball.  Last year he had a torn conipsis."
Me: "Huh?  What is a conipsis?  Oh, wait.  MENISCUS!"! [I proceed to fall on the floor laughing]

I will never forget that one.