Greenfield doesn't have a lot, but what it does have is a little gem called Hough's.
As other reviewers have said, the beer list does not disappoint. The specials are fairly good and the staff is quite knowledgeable about the brews. The burgers are the best of their food fare and don't get me wrong they are quite delicious, however the rest of the food is standard and unimpressive. If you're going to Hough's, you're usually going for the atmosphere and the brews, not so much to have fantastic food.
On the outside, Hough's doesn't look impressive, but inside it is quite spacious, clean, and has a nice atmosphere. This is one of my favorite bars in the city to watch Penguins games. Added bonus: this bar has a kickin' dartboard machine AND shuffleboard.