From R. Dr. David Berger, via R. Dr. Jeffrey Woolf:
A yeshiva bochur asked his rebbe if it's muttar to go to the opera. The rebbe replied, "You're not over till the fat lady sings."
To understand this one line, you have to know about kol isha, you have to know yeshivish, and you have to know the American expression about the fat lady.