Hampden isn’t what is used to be. Once a strange amalgam of white working-class culture and post-art-school bohemians, the neighborhood is now home to $30-a-plate dining, an organic supermarket, even a charcuterie bar. Still, remnants of Old Hampden can be found holding tight if one is paying attention. Griffith’s Tavern, a block north of The Avenue, is a classic dive with wood paneling and a cigarette machine behind the bar, and it is still a second home for many old Hampdenites. Plus, this single-room joint offers $2.50 pints of Boh and carry-out on Sunday.