Tie-dyed Pink Floyd 'relics' t-shirt from the mid-seventies. It still comes out at retro parties, halloween, etc... The floyd are making something of a come back and my seventeen year old nephew has his eyes on it.
I have one I can't put an age on. It is used for waxing my vehicle. I will submit it for some Carbon-14 tests to see if I can get the age of it. Given the blackening of the armpits from aluminum in deodorant, it can't be too old.
I found a couple of Blue Oyster Cult shirts from the Mirrors tour (1979) and Cultosaurus Erectus tour (1980) in my old room in my Dad's house last year (cleaning out some old old stuff). And they have drastically shrunk somehow! [img]images/icons/rolleyes.gif[/img]
Recent oldies but goodies... I would have to say my PADI tees from the 1998 DEMA show in Anaheim. The armpits are kinda holey, the rest is a little ragged, but they still fit and I wear them when doing yard work (used to be on the beach while teaching). I have a couple of other tees from the old diveshop trip to Bonaire in 1993. Still in decent shape, but a little tight now.
Otherwise my wife does what she calls "midnight recs" on my clothes every couple of years to get rid of the old stuff. I am not a clothes horse, just have "favorites" that are worn routinely.