thank you Erik Weber and his buddy Matthew Beischer for pointing this out:
TOO Day in once upon a Simpsons timeline, Lisa was supposed to have aged enough to be married to a Hugh Grant clone. Think about that, and now you feel 157 years old. A sunday wedding!
From season 6, episode 19, 1995.
Other things that were supposed to have occurred by Simpsons 2010:
Bart married and divorced three times
World War III
Scientists discovering a cure for 15 stab wounds in the back (but not quite 17)
Lisa and Millhouse did it
Things that actually have happened: