This band invokes a darker mood, though not grim.They have a sound similar to Beirut, as they utilize an orchestral sound, but that is also distinct from Beirut. Where Beirut often sounds like they are taking influences from the circus or carnival, Dark, Dark, Dark sounds like they are using influences from Eastern Europe. A darker, melancholy, Eastern European, orchestral sound.
My own experience with Dark, Dark, Dark started with brief exposure to as they were played on The Current. Then I downloaded one of their Daytrotter sessions, which I highly recommend. But the thing that did me in about them was when I saw them perform for The Walker's Music and Movies in the Park. They were commissioned to write and perform a live score to go along with the 1938 silent German film SPIES. The following video is part of that live score and is of one of the greatest live music experiences I've ever experienced (though you must forgive it, as the sound quality is not the greatest).
Oh, and you can find a free download of their single "Daydreaming" over at Bandcamp!