TONIGHT: Stephen Colbert welcomes journalist, Fareed Zakaria!

TONIGHT: Stephen Colbert welcomes host of Lou Dobbs Tonight, Lou Dobbs!

TONIGHT: Stephen Colbert welcomes author of "It's Called a Breakup Because It's Broken: The Smart Girl's Break-Up Buddy", Greg Behrendt!

TONIGHT: Stephen Colbert welcomes astrophysicist and author of "Origins: Fourteen Billion Years of Cosmic Evolution", Neil DeGrasse Tyson!

TONIGHT: Stephen Colbert welcomes actor, Jeff Daniels!

TONIGHT: Stephen Colbert welcomes author of "Where God Was Born: A Journey by Land to the Roots of Religion", Bruce Feiler!

TONIGHT: Stephen Colbert welcomes star of The West Wing, Bradley Whitford!

TONIGHT: Stephen Colbert welcomes the New York State Attorney General, Eliot Spitzer!

TONIGHT: Stephen Colbert welcomes CourtTV anchor, Catherine Crier!

TONIGHT: Stephen Colbert welcomes Reverend Al Sharpton!

TONIGHT: Stephen Colbert welcomes author of "Spanking the Donkey", Matt Taibbi!

TONIGHT: Stephen Colbert welcomes star of Zathura, Tim Robbins!

Tonight Stephen welcomes former White House Press Secretary Scott McClellan, author of What Happened: Inside the Bush White House and Washington's Culture of Deception, Scott McClellan. Also, Stephen talks with former Georgia Representative and Libertarian Presidential candidate Bob Barr about the Libertarian party's "green" efforts.