In a weekend of so much to do here in the Philadelphia region, if under the threat of something really, really super-terrible-bad(!), here's what I'd recommend that you check out...if you asked. No favoritism at play here, just a recognition of some of the most interesting that the region has to offer.
Thursday===Rob Tod and his Allagash beer is loosed on the city and the suburbs --- great reason to start your weekend early as Rob makes no less than 4 stops from city to the 'burbs.
Friday===City=Firkins at Varga (Flying Fish) Rural=Cask Ale Festival in Lititz, near Lancaster --- This brings together Alex Hall (NYC) and Paul Pendyck (General Sutter Inn, et al) for the first of its kind in charming Lititz
Saturday===Craft Beer Express around Philly --- choose the bus and do it all day. or meet up with the revelers along the way at a place of your choosing. How can you go wrong? Just stay out of the way of that "other green bus." In the suburbs, try the Imperial IPA Fest at The Drafting Room
Sunday===Brewers Plate --- one of the regions premier beer and food events. I've written about it several times in the past (in 2006, in 2007, in 2008, in 2009) and it really doesn't get much better than this. As of yesterday, less than 100 total tickets remain. This will almost certainly sell out prior to the event.
Monday===Wanna make a long weekend for yourself? Check this out Brooklyn Beer Dinner at Barclay Prime