I went here last week with a group of friends and was really amazed at how good the happy hour appetizers were. Like other restaurants, Dupont Grille offers 5 appetizers for $5, and $5 drinks. Here they offer 5 types of wine and 5 different martinis. We ordered the plate of 3 sliders (mini burgers) which were delicious, as was the small beef shortrib with mashed potatos, and hummus with pita (the hummus comes in a martini glass). Very high quality at a low price.
We were there on a Friday night, but it wasn't very busy. It's a small area, very relaxed. I thought it was a really nice place to unwind after work, without the loudness of some after-work bars. The bar itself sits all of 4 people, but we were able to sit at a table and get our happy hour priced items. You have to be quick though--it only runs from 5:00-6:45pm, but on the plus side happy hour is offered 7 nights a week.