On May 23rd of 2007 the American Library of Congress brought together various singers and musicians to honour and celebrate the music of Paul Simon. At the event in the Warner Theatre in Washington DC Paul Simon became the first recipient of the Gershwin Prize for Popular Song. The other award recipients since then have been Stevie Wonder in 2008, Paul McCartney in 2009 and most recently Burt Bacharach and Hal David in 2011.
The inaugural event in 2007 featured singers such as Stevie Wonder, James Taylor, Lyle Lovett, Yolanda Adams and Art Garfunkel. One of the most beautiful performances was by Alison Krauss and Shawn Colvin who were accompanied by Jerry Douglas on slide guitar.
Here is that performance.