You could do a barleywine, ~20 lbs of mostly MO, plus some wheat and vienna (and maybe some caramel or a touch of chocolate). Give it ~65 IBUs of hops for bittering (no need for aroma hops as it will be long gone by the time you drink it). Ferment with the American or British yeast strain of your choice (pitch loads of yeast and try to keep fermentation temps down in the 60s.)
Other good aging candidates are big stouts, wee heavies, sour beers, doppel/eisbocks, old ales, quads etc… (big, dark, sour all help aging).
Should be tasty for many healthy years to come.