I have a craving for beef, but as always, I'm on a budget. Any recs for the best place to get a mouth-watering piece of meat for under $20? Suburbs and chains are excluded, of course, but any other restaurants in Boston, Cambridge, Brookline, etc. will be considered. Please refrain from Boston Chowhound favorites (e.g. NO EAST COAST GRILL!) and I'd prefer not to have to dress up, although that shouldn't be an issue at $20/plate.