Grandpa Simpson mentions Eddie Gaedel, the shortest player in major league baseball. Edward Carl Gaedel was an actual player for the St Louis Browns baseball team in 1951.
Weighing 65 pounds and standing 3 feet 7 inches tall, Gaedel became the shortest player in the history of the Major Leagues. He made a single plate appearance and was walked with four consecutive balls before being replaced by a pinch-runner at first base. His jersey bearing the uniform number 1/8 is displayed in the St Louis Cardinals Baseball Hall of Fame and Museum
Bart paid Gil $50 to walk up the down escalator all day. Minimum wage at the time this episode aired was $7.25 an hour. Working 8 hours at a minimum wage job would net Gil $58 pre-tax.
The title is a reference to the Da Vinci painting "Mona Lisa".