Season 21, Episode 17
Mr. Burns is imprisoned for the theft of a painting so it is down to Mr. Smithers to take over the running of the power plant in his absence. But when he starts working the guys even harder, Homer, Lenny and Carl devise a plan to break their boss out of jail.
There are movie references to The Game, The Shawshank Redemption and The Green Mile.
See here for more details.