“The acclaimed rock and roll band”, The National played live on David Letterman’s show last night, February 1. They brought along album standout (among an album of standouts), ‘Conversation 16’. It was an intense performance, but I guess for those of you lucky enough to see them in the Olympia in December (damn you snow) that goes without saying. The album is High Violet, it’s been out for a while: it’s kind of a big deal. Hi violet! Oh David…