In the ending credits of "Dateline: Springfield", it states Guillermo del Toro designed Moe Szyslak.
El Barto tagged the Police Station.
King Toot reads all of Infinite Jest by David Foster Wallace while waiting for Lisa to finish playing the new saxophone.
Krusty was eating a lobster dipped in mayonnaise. Since Krusty was born and raised (Ashkenazi) Jewish, he did not observe the Jewish dietary laws of what is considered Kosher (no shellfish or mayonnaise).