Ok well, you guys have made it easy for me because 13 is also my favorite moment in the entire series (6 is up there too), but I was thinking for this one I might go with 14 since even though 13 happens AT a party, the moment is about Luke and Lorelai so 14 felt a little more appropriate for the category. Since there's a consensus though, I definitely don't need much convincing ;-).
13 for the win.