@Haley House Bakery Cafe - a non-profit restaurant that offers healthy food and deeeeeeelicious pies! Their pie proceeds this month are going to the Transitional Employment Program
Not sure if it's actually considered a "dive bar", but @Joe Sent Me in Waltham is a pretty cool place with zero frills. Definitely go on a Tuesday night! (The Bentley crowd fills it up quite nicely).