Head over to Penn Brewery in Deutschtown for the Pennsylvania Microbrewers Fest 2015 on Sat., June 6, 2015. At least 25 breweries will be pouring samples. Food from Penn Brewery will also be available. Tours of the Penn Brewery facility will be ongoing throughout the night ($10 additional), as will live music.
They have a nice list of breweries coming on their website. Many local breweries will be there, plus some national ones (such as newcomer to our region Sweetwater Brewing).
Tickets start at $50 and are available here.