Quarry House is definitely your best bet. I used to live not far from there. I believe they're open every night, at least they used to be. I rode out all those huge blizzards there a while back. Can't find information now, but I believe Monday was 1/2 off burger night, which was cool. Burgers aren't bad at all. Wednesday (i think) is whisky night where you get maybe half (can't remember) off whisky, and they have a surprisingly huge and well-stocked scotch selection.
Jackie's Sidebar is really good, but a couple blocks walk (8081 Georgia Ave) further past Quarry House. Cocktail bar, with very limited food options.. but what they do serve is absolutely delicious.
Closer by in the downtown silver spring area is a strip mall Irish Pub type place (McGinty's), which is serviceable and pretty standard. The best food in that area is certainly Nando's though.
A different option would be to head to Mi Rancho for some delicious margaritas and not-to-shabby tex mex. Walk down Colesville, cross Georgia, turn right at the Qdoba and up the hill which is Ramsey Avenue.
If you do head to Quarry House, it's directly under the Bombay Gaylord Indian Restaurant (which is quite good), Langano Ethiopian is a bit further down and pretty good as well. Whatever you do, don't be tempted to go the Piratz Tavern. It's sounds like it should be great.. but it's really not.