When Lisa calls Homer about the saxophone reed, he writes the specifications on the sole of his left foot. Later, when talking to the music store guy, Homer reads off his right foot.
Homer tries to cash a $10,000 ticket at the Kwik-E-Mart. However, many state lotteries have limits on how much a retailer can cash. Hoosier Lottery, for example, allows retailers to cash up to $500. Further, a convenience store like Kwik-E-Mart would likely refuse a $10,000 payout because they wouldn't have the cash on hand.
Homer's calendar at work shows November started on Sunday, but November in 1991 started on a Friday.
Homer is hired to work the 12am-8am shift at the Kwik E Mart, but when Bart is bothering him at the store, it is daytime. However, depending on the time of year, the sun could very well be up for hours of this shift.
When the boys from school are watching Lisa ride her pony, Ralph speaks with Nelson's voice.
Principal Skinner informs the audience that the doors have been locked, however, when Homer arrives, he opens the door easily.