Park Slope hardly seems like it would be hip enough to attract men who are not gay but have big muscles and wear tight, trendy shirts. You know, chiefs, meatheads, jocksdouche bags. And yet, they're trickling down Fifth Avenue, and I fear we'll soon be awash. But we needn't retreat to dives (although we usually do)try Commonwealth for chief-free class. Opened by nice guy Ray Gish, who formerly tended for slake-superior Great Lakes, and his partner, Roy Dwyer, who runs the Slope's best Thai restaurant, Long Tan, Commonwealth is far from disheveled, but it's no yupster lounge. I'm told the mahogany bar came out nicer than the owners intended; everythingcomfy chrome-and-vinyl seating, various wall paintsmatches in this thoughtfully eclectic way, and you could even describe the indie-plus juke as tasteful (Cornershop, Os Mutantes, Archers of Loaf). For six bucks apiece you can get 20 ounces of Guinness and a generous cup of delicious Kentucky beer cheese with a bunch of crackers. Good bar food that's not "tapas," wings, or otherwise inspired by sports: reason enough to deem the place a true original.