There is no more natural pairing in the world than beer and the coffee bean. The deep roasted flavors of dark beers like stout, Schwarzbier (black lager), porter, doppelbock and others lend themselves perfectly to the beautiful, black, bitterness of coffee.
The craft beer renaissance has seen an explosion this favorite beer adjunct. There is hardly a brewery that doesn't have at least one coffee beer either in their regular lineup or featured as a favorite seasonal.
Read more here: http://beer.about.com/od/beerstyles/tp/coffeebeer.htm
Happy National Lager Day!