"500 Keys" is the twenty-first and penultimate episode of the twenty-second season of the American animated television series The Simpsons.
[1] In this episode, the Simpson family has adventures with the keys they have hoarded over the years, which leads Lisa to a mystery at Springfield Elementary.
The episode received mixed reviews The Simpsons return home, but Maggie gets locked in the car.
Skinner cashed the check but left the money in his pants pocket, and his mother destroyed it washing his laundry.
Later, Otto drives his bus across an icy bridge, believing his passengers are mannequins but is transporting real children.
"[2] The chalkboard gag was written to correct the error from the previous episode "Homer Scissorhands" where guest star Kristen Schaal's surname was spelled incorrectly as "Schall" in the credits.
During the closing credits, the jingling of a set of keys is heard, followed by a solo violin rendition of the show's theme.
In its original American broadcast on May 15, 2011, "500 Keys" was viewed by an estimated 6 million households and received a 2.5 rating/7 share among adults between the ages of 18 and 49.