Perpetual Saturdays

That period of time for teachers that is simply known as 'summer' to the general populace.

It refers to the fact that during the summer months, teachers "don't have to work today or tomorrow." Thus, making every day a Saturday.

Joe Plumber: "sorry man, I can't come out tonight. I gotta work tomorrow."

Frank the Teacher: "you're working in a Saturday?"

Joe Plumber: "tomorrow's Tuesday!"

Frank the Teacher: "huh, feels like a Saturday ..."

Joe Plumber: "damn Perpetual Saturdays ..."