500 Keys/References

Trivia

 * Lisa's saxophone is replaced with a violin in the opening sequence.
 * We learn Maggie can use the keys without help from her family.
 * The aired version of the chalkboard gag is an apology to Kristen Schaal for misspelling her name in the credits for "Homer Scissorhands".

Goof

 * How do the people whom the Simpsons got the keys from not know about the family taking them? They would've known by the time they found them.