wikipedia will tell you;
Flight of the Conchords is a Grammy Award-winning New Zealand comedy duo composed of Bret McKenzie and Jemaine Clement. Billing themselves as "Formerly New Zealand's fourth most popular guitar-based digi-bongo acapella-rap-funk-comedy folk duo", the group uses a combination of witty observation, characterisation and acoustic folk guitars to work the audience. The duo's comedy and music became first the basis of a BBC radio series and then an American television series, which premiered in 2007, also called Flight of the Conchords.
Named Best Alternative Comedy Act at the 2005 US Comedy Arts Festival, Best Newcomer at the Melbourne Comedy Festival, and receiving a nomination for the Perrier Comedy Award at the Edinburgh Fringe in 2003, the duo's live performances have gained them a worldwide cult following.
personally, I think they're pretty dam amazing and me I have watched through the whole of season one about 3 times now.