I had these[/url:30ph2hof] recently in Belgium
from left to right
Diesters (from 1980ish)
Duvel (from the 1970's...post 73 anyway)
Trappist Sint-Bernadus (from the 1950's)
Westvleteren 8 (pre 1969)
Kappitel Prior (from about 1970)
Westmalle Tripel (early 80's)
Westvleteren 8 (pre 69)
Leffe Dark (late 60's/early 70's)
Gouden Carolus (1989)
Rodenbach (1964)
Maes Pils (1960's)
Aigle Belgica: Dobbel Blond (table beer from the 60's)
Sint-Bernadus Westvleteren 12 (late 80's)
Floreffe Dark (70's)
I picked up a couple of De Molen beers at the weekend and the labels say the beer can be aged for up to 25 years