Incredibly funny. Check it out on this link to MSN Video!
It is part of his goodbye-CES speech. fetured guests include Brian Williams, Steve Ballmer, Matthew McConaugheyr, Robbie Bach, Jay-Z, Bono, Steven Spielberg, George Clooney, Jon Stewart, Kevin Turner, Hillary Clinton, Barack Obama, Al Gore, Ray Ozzie and Craig Mundie,
Seems a higher-res version is found here http://www.istartedsomething.com/20080107/bill-gates-last-day-microsoft-video/