Homer and Ned's escapades in Vegas lead to them having an adventure straight out of The Hangover well before The Hangover was ever conceived, back in "Viva Ned Flanders." However in season eighteen we learn that Amber Simpson, Homer's ex, has died, of a drug overdose while at an amusement park - the ultimate oxymoron. The importance of the sign, you ask? Well, the joke goes as follows (when Bart asks how she died): Lenny: Ill tell you how she died. You know that sign that says, Do Not Stand Up on the Rollercoaster? Bart: Yeah. Lenny: She overdosed right in front of it.