Lena Dunham; Max Greenfield; Brandy Clark

Joel McHale; Marv Albert; Washed Out

Scarlett Johansson; John Grant

Anderson Cooper; Bobby Moynihan; Will Hoge

Mindy Kaling; Jeff Altman; Red Fang

Bill Cosby; Sleigh Bells

Michael Strahan; Jennifer Nettles

Kevin Hart; Mo Rocca; The Orwells

Brian Williams; Rosanne Cash

Don Cheadle; Myq Kaplan; Roadkill Ghost Choir

Andy Samberg; Michael B. Jordan; Ellie Goulding

Martin Scorsese; Allison Williams; Cults

Rachel Maddow; Spike Jonze; No Age

Kevin Bacon; Pat McGann; Devon Avenue

Louis C.K.; B.J. Ganem; Artic Monkeys

Eric Stonestreet; Nick Goepper; Bastille

Drew Brees; B.J. Novak; Against Me!

Dr. Phil McGraw; Danny Koker; Dum Dum Girls

Bill Murray; Eagulls

Will Arnett; Broken Bells

George Clooney; Sting

Matt Damon; Lenny Kravitz

Patrick Stewart; The Flaming Lips

Regis Philbin; Ms. Lauryn Hill

Kevin Spacey, Amber Heard, a Top Ten List presented by the cast of

Sage Kotsenburg, Kate Mara

Kaitlyn Farrington, Lupita Nyong'o, Little Dragon

Keri Russell, Terry Fator

Pauley Perrette, Jeff Caldwell, Lake Street Dive

Kaley Cuoco-Sweeting, Dale Earnhardt, Jr., The Fray

Olympic Gold Medalist Ted Ligety, Kat Dennings, Lo-Fang

Meredith Vieira, Band of Horses

Stupid Human Tricks, Simon Helberg, Young the Giant

Jack (Jungle) Hanna, Jake Johannsen

Zach Braff, Sgt. Brendan Marrocco & Dr. Andrew Lee, Future Islands

Michael Keaton, Phantogram

Tom Selleck, Carrie Brownstein, David Nail

Tom Brokaw, Andrew Hadlock, Bob Mould

Mary-Louise Parker, Lenny Marcus, Joan Jett & the Blackhearts

Sen. John McCain, Little Mix

Jason Bateman, Miles Teller, Gary Allan

Sylvester Stallone, Theo James, Ledisi

Bryan Cranston, Melissa Rauch, Le1f

Bill O'Reilly, Nick Griffin, the Dough Rollers

Jimmy Carter

Emma Watson, Nick Offerman, a musical tribute to Johnny Cash

Peter Dinklage, Hari Kondabolu, Sage the Gemini

Cobie Smulders, Nick Cannon, Manchester Orchestra

Kristin Chenoweth, Amy Schumer, Johnnyswim

Bill Murray, Martha Stewart, Lady Gaga

Johnny Depp, Kevin Drew

Billy Crystal, Tony Hale, Liv Warfield

Rob Lowe, Brooklyn Decker, London Grammar

Lindsay Lohan, Jamie Edwards, Real Estate

Courteney Cox, Jimmie 'J.J.' Walker, Christina Perri

Stephen Colbert, Robin Roberts, Kelis

Sally Field, Timothy Simons, Needtobreathe

Neil Patrick Harris, Sarah Hyland, Ray LaMontagne

Piedmont Bird Callers, Michael J. Fox, Naughty Boy

Joel McHale, Vera Farmiga, Aloe Blacc

Lucy Liu, Ziggy Marley

Kiefer Sutherland, Adam Resnick, Benjamin Booker

Louis C.K., a performance from the Broadway cast of Rocky

Don Rickles, Carmen Lynch, the Ghost of a Saber Tooth Tiger

Shailene Woodley, Peyton Manning

Jon Cryer, Elizabeth Olsen, Foster the People

Mariah Carey, Rick Harrison

James Franco, Idina Menzel, a performance by the Broadway cast of 'If/Then'

Nathan Fillion, Tom Dreesen, Hunter Hayes

Harry Connick Jr., Jesse Eisenberg, the Black Keys

Jim Parsons, Julie Chen, Hozier

Barbara Walters, Elle Fanning, Randy Houser

Adam Sandler, Thomas Haden Church

Lea Michele, Andy Kindler, Chromeo

Jack Hanna, Stephen Malkmus & the Jicks

Kid scientists, Sarah Silverman, We Are Scientists

Sgt. Kyle J. White, Judy Greer, Dierks Bentley

Donald Trump, Indianapolis 500 winner Ryan Hunter-Reay, Elizabeth Cook

Martin Short, John Oliver, Spanish Gold

Anderson Cooper, Victor Espinoza, the Afghan Whigs

Kelsey Grammer, Willie Nelson

Dave Chappelle, Laura Prepon, a Top Ten List presented by Miss USA, the Orwells

Christopher Walken, Janelle Monae, Tatiana Maslany, Miss USA 2014

Regis Philbin, Paul Morrissey, First Aid Kit

Susan Sarandon, Whitney Cummings, Angel Olsen, David Sanborn

Olivia Wilde, Shep Gordon, Empires

Dana Carvey, Ellie Kemper, Sam Smith

Paul Rudd, Jeff Altman, John Doe

Adam Levine, Gen. Frank J. Grass, Broken Bells

Melissa McCarthy, Rachelle Lefevre, Phish

Mark Wahlberg, Ben Falcone, Hurray for the Riff Raff

Mark Ruffalo, Former Marine Lance Cpl. William 'Kyle' Carpenter

Halle Berry, Steve Young, War on Drugs

Joan Rivers, Capital Cities

Lizzy Caplan, Sleeper Agent

Michael Douglas, Paul Morrissey, Kiesza

Kurt Russell, Hannibal Buress, Sturgill Simpson

Jason Segel, Liv Tyler, Trampled By Turtles

Emma Stone, Nathan Fielder, American Authors

Colin Firth, Tommy Johnagin, EMA

Jeff Daniels, Norah O'Donnell, A Special Performance of 'MacArthur Park'

Ricky Gervais, Taylor Schilling, Eli Young Band

Eric Stonestreet, Brody Dalle

Staff Sgt. Ryan Pitts, Sharon Van Etten

John C. Reilly, Rachelle Lefevre, Conor Oberst

Chris Pratt, Rodrigo y Gabriela

Zoe Saldana, Crash

Julia Louis-Dreyfus, Simon Amstell, David Gray

Bruce Willis, the Gaslight Anthem

Joseph Gordon-Levitt, Novak Djokovic, Robby Johnson

Kathy Griffin, Ken Burns, Jeremy Messersmith

Serena Williams, Chadwick Boseman, Echo & the Bunnymen

Michael Cera, dock diving dogs, Lyle Lovett

Howie Mandel, EMA

James McAvoy, Chris Russo, The Last Internationale

Mike Myers, Bonnie McFarlane, John Fullbright

Luke Wilson, Julie Chen, Lee Brice