Brian Williams, Paula Abdul

Tim McGraw, Shaquille O'Neal, Keri Hilson

Jennifer Connelly, Dr. Oz, Justin Townes Earle

Seth Rogen, Beau Garrett, the Walkmen

Regis Philbin, Hannibal Buress, No Age

Bill Cosby, a Top Ten List presented by Nicole "Snooki" Polizzi, the Black Keys

Vince Vaughn, Mike Wolfe & Frank Fritz, Cage the Elephant

Kevin James, Olivia Munn, The Low Anthem

Kelsey Grammer, Amar'e Stoudemire, Gregg Allman

Joan Rivers, Jeff Caldwell, Wintersleep

Jack Hanna, Steven Tyler

Betty White, Kim & Kourtney Kardashian, the Script

Martin Short, Greta Gerwig, Darius Rucker

Kaley Cuoco, Piers Morgan, Wanda Jackson, Miss Arkansas, Alyse Eady

Nathan Lane, Mike Palascak, Esperanza Spalding

Justin Bieber, Pauley Perrette, Best Coast

Matthew Perry, Chris Elliott, Top Ten with Mitt Romney, the National

Kate Walsh, Jim Gaffigan, Boxer Rebellion

Howard Stern, Naughty By Nature

Martha Stewart, Top Ten with Justin Bieber, Robert Plant

Super Bowl MVP Aaron Rodgers, Martin Lawrence, Steel Magnolia

Adam Sandler, Chris Colfer, Gang of Four

Anderson Cooper, Elton John

Nicole "Snooki" Polizzi, Judah Friedlander, Bryan Ferry

Ed Helms, Ted Alexandro, Steel Magnolia

S.I. Swimsuit Cover Reveal & Top 10, Tom Brokaw, Theophilus London

Forest Whitaker, S.I. Swimsuit Cover Model Irina, Josh Groban, Top Ten with Joy Philbin

Bill Hader, Grocery Bagging Champ Krystal, Amos Lee

Paris Hilton, Nathan Fillion, Scissor Sisters

David Spade, Andy Kindler, Lukas Nelson and Promise of the Real

Donald Rumsfeld, Cobie Smulders

Amy Poehler, Jean Chu and Dusty the Cat, Deerhunter

Rainn Wilson, Hank Aaron

Senator Rand Paul, Bright Eyes

Matthew Morrison, Jeff Altman, Jessica Lea Mayfield

Brian Williams, Trey Parker & Matt Stone, Zac Brown Band

Amanda Seyfried, B.J. Novak

Donald Trump, Vanessa Hudgens, Oh Land

Robin Williams, Judy Greer

Charles Barkley, Sarah Vowell, Cold War Kids

Bradley Cooper, Mindy Kaling, Bob Geldof

Steve Martin, Selena Gomez

Dana Carvey, Dr. Michio Kaku, British Sea Power

Katie Couric, The Pains of Being Pure at Heart

Ben Stiller, Dario Franchitti, The Strokes

"Jungle" Jack Hanna, Danny McBride

Regis Philbin, Snoop Dogg

Norm Macdonald, CC Sabathia, Willie Nelson, Norah Jones and Wynton Marsalis

Chris Rock, Ellen Page, Funeral Party

James Franco, Royal Bangs

Jennifer Garner, Jamie Oliver, Robbie Robertson

Don Rickles, Eva Longoria

Alec Baldwin, Wiz Khalifa

Ricky Gervais, Top Ten with Katie Holmes, Foo Fighters

Courteney Cox, Aziz Ansari, Alison Krauss & Union Station featuring Jerry Douglas

Seth Meyers, Carmelo Anthony, TV on the Radio

Tina Fey, Tommy Johnagin, The Gaslight Anthem

Bill Maher, Cote de Pablo, Lupe Fiasco

Will Ferrell, The Twilight Singers

Kate Hudson, Rich Eisen, Emmylou Harris

Dr. Phil McGraw, Chris Hemsworth, Broadway musical "Catch Me If You Can"

John Krasinski, Brian Kiley, Steve Earle

Brian Williams, Rex Ryan

Caroline Kennedy, Ty Burrell

Betty White, Rick Harrison, Morning Teleportation

Jodie Foster, Tom Dreesen, Neon Trees

Bill Murray, ''The Human Fuse'' Brian Miser, Brother

Albert Brooks, Kristen Wiig

Mark Harmon, Chris Morgan, Hugo

Stupid human tricks, Jim Parsons, Manchester Orchestra

Joan Rivers, Nick Griffin, Okkervil River

Julianna Margulies, Andy Cohen, a Top Ten List presented by Christina Aguilera, White Lies

Martin Short, Melissa McCarthy, Tinie Tempah

Keith Olbermann, Julie Bowen, Ben Harper

Kelly Ripa, Jennifer Lawrence, How to Succeed in Business Without Really Trying

Tracy Morgan, Jake Johannsen, The Airborne Toxic Event

Lady Gaga, Eric Stonestreet, The Vaccines

Ewan McGregor, Scott Pelley, Brad Paisley

Piedmont Bird Callers, Kevin Bacon, Augustana

Ray Romano, Reese Waters, Arctic Monkeys

Meredith Vieira, Indianapolis 500 winner Dan Wheldon, Drum Solo Week kicks off with Anton Fig

Kyle Chandler, Kathy Griffin, Sheila E.

Jon Cryer, Rachel Maddow, Roy Haynes

Neil Patrick Harris, Mike Birbiglia, Neil Peart

Adm. Michael Mullen, Top Ten by Betty White, Black Joe Lewis & the Honeybears

Ryan Reynolds, chef Eric Ripert and the cast of the Broadway musical Anything Goes

Samuel L. Jackson, Texas Ranger Josh Hamilton, Jennifer Hudson

Cameron Diaz, Eddie Vedder

Jason Bateman, Amy Sedaris, Top Ten by Keith Olbermann, Drive-By Truckers

Kevin James, pet fashion designer Ada Nieves, Beady Eye

Jason Segel, horse whisperer Buck Brannaman, Noah and the Whale

Shia LaBeouf, Bert Kreischer, Dawes

Tom Hanks, Sleepy Man Banjo Boys

Patrick Dempsey, Erica Hill, Marty Stuart

Julia Roberts, Cake

Emma Watson, George Lopez, Incubus

Roseanne Barr, Tom Felton, Blake Shelton

Ryan Gosling, Gomez

Kyra Sedgwick, Tim Harmston, Nikki Jean

Bono & the Edge, a performance from Spider-Man: Turn Off the Dark

Steve Carell, Hope Solo and Abby Wambach, The Del McCoury Band and the Preservation Hall Band

Jeremy Piven, Captain Luis Montalvan, Cee-Lo Green

Harrison Ford, Porcelain Black

Brian Williams, Tim Robbins & the Rogues Gallery Band

Julianne Moore, Johnny Galecki, Tanner Foust, Eels

Craig Ferguson, Connie Britton, Anna Calvi

Kirstie Alley, Louis C.K., Fountains of Wayne

James Franco, Dianna Agron, Christina Perri

Ricky Gervais, Cat Deeley, Explosions in the Sky

Emma Stone, Alan Mulally, Sallie Ford

Colin Farrell, Christopher Ferguson, Typhoon

Denis Leary, Elizabeth Cook, Drum Solo Week II kicks off with Tony Royster Jr.

Rachel Maddow, Rose Byrne, Gavin Harrison

Ashton Kutcher, Rafael Nadal, Stewart Copeland

Paul Rudd, Bill Burr, Dennis Chambers

Jason Sudeikis, Bettina Luescher, St. Vincent

Alec Baldwin, Joe Namath, Lenny Kravitz

David Arquette, Aubrey Plaza, Thurston Moore

Julianna Margulies, Joe Wong, Lady Antebellum

Kim, Kourtney & Khloe Kardashian, Michael Emerson, The Jim Jones Revue

Sgt. 1st Class Leroy Petry, Sarah Jessica Parker

Michael J. Fox, Top Ten by the cast of Two and a Half Men, Jim McDonald, John Doe

Dr. Jill Biden, Ted Danson

Jonah Hill, Paula Abdul, Coldplay

Taylor Lautner, Minka Kelly, Wilco

Sergeant Dakota Meyer, Sofia Vergara, Chris Cornell

Nathan Fillion, Larry Miller, The Jayhawks

Seth Rogen, Poppy Montgomery, Fleet Foxes

Jack Hanna, Anna Faris

Anderson Cooper, Nick Offerman, The Knux

Kaley Cuoco, Skipper Bivins & Trent Jackson, Death Cab for Cutie

Samuel L. Jackson, Karen Rontowski, Anne-Sophie Mutter

Brian Williams, Sting

Hugh Jackman, Sean Young, Feist

George Clooney, Mastodon

Caroline Kennedy, dock diving dogs, The Joy Formidable

Bryan Cranston, Jeff Altman, Garland Jeffreys

Tracy Morgan, Mike Golic & Mike Greenburg, Mates of State

Matthew Broderick, horse wrangler Erin Bolster and her horse Tonk, Hunter Hayes

Bill Clinton, Deer Tick

Bill O'Reilly, Martina McBride

Artie Lange, Eddie Brill, Beirut

Salma Hayek, Keith Olbermann, Jane's Addiction

Eddie Murphy, Jane Levy, Mayer Hawthorne

Justin Timberlake, Jennifer Esposito, The Civil Wars

Johnny Depp, Foster the People

Tom Brokaw, Myq Kaplan, The Head & The Heart

Tony La Russa, Jesse Eisenberg, Puscifer

Ben Stiller, Whitney Cummings

Condoleezza Rice

Mark Harmon, Mike Judge, Top Ten by Matt Lauer, Eli Young Band

Bill Cosby, Jason Isbell and The 400 Unit

Melissa McCarthy, Anthony Bourdain, Joan Baez & Kris Kristofferson

Robert Pattinson, Annie Leibovitz, David Crosby and Graham Nash

Adam Sandler, Peter Gabriel

Stupid Humans Tricks, Katie Holmes, Noel Gallagher's High Flying Birds

Steve Martin, Felicity Jones, Lonesome River Band feat. Steve Martin

Jason Segel, Jamie Oliver, The Kooks

Bill Maher, Nikki Reed, Foo Fighters feat. Joan Jet

Jerry Seinfeld, Lykke Li

Regis Philbin, John Fogerty

Herman Cain, Grouplove

Andy Kindler, Ty Burrell, Gayle King, Needtobreathe

Amy Sedaris, Christopher "Mad Dog" Russo, Sondre Lerche

Justin Bieber, Brian Regan, FreeSol

Jonah Hill, Kristen Johnston, Ryan Adams

Matt Damon, Shelby Lynne

Jessica Biel, Tom Dreesen, The Black Keys

Charlize Theron, Kevin Nealon, Blitzen Trapper

David Duchovny, Comedian Hugh Fink, Young Jeezy

Scarlett Johansson, Julie Chen, Top Ten by the 2011 Heisman Trophy winner Robert Griffin III

Barbara Walters, Bill Hader, Wild Flag

Robert Downey Jr., Rooney Mara

Tom Hanks, My Morning Jacket

Jude Law, Bob Sarlatte, Gary Clark Jr.

Tom Cruise, Anthony Hamilton, Top Ten by Mitt Romney

Harry Connick Jr., Scott Van Pelt, Mariachi El Bronx

Jon Huntsman, J. Cole

Anderson Cooper, Lindsey Vonn, Childish Gambino

Jay Thomas, David Hyde Pierce, Darlene Love