could be a doable visit for you - just off the route 30 exit from 476, west of Villanova. I'll inbox you details if you want.

They have a fair amount of dated stuff on the shelves, but once it hasn't moved they have a little section of past-due stuff that they mark down. Markdown % will depend on who's working at the store then but is typically 40%. The irony is that for some of those strong beers, aging is actually considered desirable - so you're getting a better version of the beer at a lower price. Not always, though - that Gulden Draak isn't awesome, and I've had a case of De Ryck Special from the discount rack that was also probably past due.
Most of the beers back there are seasonals from one or two seasons ago, though.

Occasionally they get rid of those discount cases by doing bottle blowouts at a nearby bar, so it can be really hit or miss.

I've actually been planning to head in to see if they have the Belgian Christmas ales on markdown yet. Typically since those are big-ticket items they'll mark 'em down in late spring.

*edit* I've had my eye on some of this http://www.beeradvocate.com/beer/profile/184/53946/ (the shop actually has cases from more than one batch) but haven't been able to justify the $200+ price tag yet, and of course in PA you can't buy singles....