They can be from the end of movies or on TV segment or whatnot,
http://www.youtube.com/watch?v=n5dLevTRF-0 (http://www.youtube.com/watch?v=n5dLevTRF-0) Desert Punk disc 6
http://www.youtube.com/watch?v=CG2T7upUVAk&feature=related (http://www.youtube.com/watch?v=CG2T7upUVAk&feature=related) Monsters Inc.