The song is called Prisencolinensinainciusol, written by Italian artist Adriano Celentano in 1972. Recorded by Celentano and Claudia Mori in an American accent, it sounds like it should be English, but the lyrics are pure gibberish. Link -via Metafilter
http://www.youtube.com/watch?v=S00Br2SSrY8
http://www.youtube.com/watch?v=vwyuB8QKzBI&feature=related