Through the decades, a parade of pop stars and actors has joined Bert, Ernie, Kermit, and Big Bird on the small screen, and these guests make up the other half of this collection's appeal. For '70s kids, Paul Simon, Pete Seeger, and Stevie Wonder dropped in for surprise visits; in the multi-culti '80s, Los Lobos, Ziggy Marley, Bobby McFerrin, and the Pointer Sisters all kept the faith. The third disc features more-modern artists -- R.E.M., the Fugees, Hootie, and 'NSync -- and also more-modern monsters. If Songs from the Street has any great flaw, it's an overabundance of songs starring the saccharine-sweet, cutesy-wootsy Muppet known as Elmo. Yet this is more than made up for by brilliant gems such as Billy Joel crooning "Just the Way You Are" to a disgusted, abrasive Oscar the Grouch and Grover singing an operatic duet with the late Madeline Kahn. These are the monsters in our neighborhood, and it's always a treat to have them over.