Robert Downey, Jr., Lenny Kravitz

Kathy Griffin, Jamie Bell, Young Jeezy

Josh Holloway, Molly Sims, Death Cab for Cutie

Simon Cowell, Paula Abdul, Nicole Scherzinger, L.A. Reid, Anna Faris, the Kooks

Jeremy Renner, Judy Greer, Chevelle

Jane Fonda, Russell Brand, Lukas Nelson & Promise of the Real

Armie Hammer, Jeri Ryan, T-Pain

Christina Applegate, Guy Ritchie, Jack's Mannequin

Matthew Morrison, Maggie Q, Yelawolf

Jim Parsons, Taylor Kitsch, My Morning Jacket

Shaquille O'Neal, Julia Jones, David Guetta featuring Usher

Regis Philbin, the Civil Wars

Morrissey

Dana Delany, David Beckham, "Dancing with the Stars" winner J.R. Martinez, Nickelback

Artie Lange, Nick DiPaolo, Atticus Shafer, Lady Antebellum

Peter Facinelli, Jamie Oliver, Vince Gill

Tim Allen, Jackson Rathbone, Miranda Lambert

Patricia Heaton, "Dancing with the Stars" finalists Rob Kardashian, Ricki Lake & J.R. Martinez, Christina Perri

Sarah Michelle Gellar, Miss Piggy, the Belle Brigade

Kristen Stewart, Jon Bernthal, Feist

Robert Pattinson, Freida Pinto, Thompson Square

Mickey Rourke, "Dancing with the Stars" castoff Nancy Grace, Wale

Taylor Lautner, Herman Cain, Junip

Eddie Murphy, Manny Pacquiao, Chickenfoot

Ellen DeGeneres, Gabourey Sidibe, Chris Isaak

Adam Sandler, "Dancing with the Stars" castoff David Arquette, the Bangles

Paul Reubens, Bruno Tonioli, Megadeth

Justin Timberlake, Rebecca Romijn, the Fray

David Spade, Tyra Banks, Brett Ratner, Frank Turner

Hugh Laurie, Nicole "Snooki" Polizzi, "Dancing with the Stars" castoff Chaz Bono

Zach Galifianakis, Mike Judge, Primus

John Goodman, Evanescence

Rob Lowe, Idris Elba, Chris Cornell

Don Rickles, "Dancing with the Stars" castoff Chynna Phillips, Peter Bjorn & John

Paula Abdul, Kenny Wormald, Two Door Cinema Club

Antonio Banderas, "Science Bob" Pflugfelder, Jane's Addiction

Will Arnett, Jane Levy, J. Cole

Evangeline Lilly, "Dancing with the Stars" castoff Kristin Cavallari, Mute Math

Jane Lynch, Ramon Rodriquez, Blink 182

Matt Stone & Trey Parker, Jessica Capshaw, Givers

Mark Wahlberg, Seth MacFarlane

Eva Longoria, "Dancing with the Stars" castoff Elisabetta Canalis, Glen Campbell

Dana Delany, Erin Andrews, Kelly Rowland

Ellen Pompeo, Sammi Giancola & Ronnie Magro, Daryl Hall

Julie Bowen, Elisha Cuthbert, Pitbull

Simon Cowell, "Dancing with the Stars" castoff Ron Artest, Gavin DeGraw

Dr. Phil McGraw, Quinton "Rampage" Jackson & Jon "Bones" Jones, Switchfoot

Steve Buscemi, Lily Collins, Ziggy Marley

Ty Burrell, Little League World Series champions, Cake

Judge Judy Sheindlin, Emily VanCamp, Staind

Nathon Fillion, Dave Salmoni and animals, Sia

Kristin Chenoweth, Freddie Wong & Brandon Laatsch

Khloe Kardashian, Ron Artest, Gabe Dixon

Elijah Wood, Jennifer Morrison, AWOLNATION

Uncle Frank Memorial Celebration, Don Rickles

Zoe Saldana, Anton Yelchin, Amos Lee

Joel McHale, Joe Mantegna, the Band Perry

Jamie Foxx, Affion Crocket, the Vaccines

Betty White, Robert Rodriguez, Josh Ritter

Jesse Eisenberg, Jerry Springer, Incubus

Jessica Alba, chef Steve Martorano, Luke Bryan

Aziz Ansari, Chris Harrison, Eric Church

Jeremy Piven, Denise Richards, Todd Glass

James Franco, Ian McMillan & Nicholas Goodfellow, Coldplay

Hank Azaria, Jim Sturgess, the Lonely Forest

Howie Mandel, "Bachelorette" Ashley Herbert, Jake Shimabukuro

Harrison Ford, Lady Gaga

Olivia Wilde, Adam Beach, Chris Young

Daniel Craig, Sasha Alexander, the Features

Jon Favreau, Rutledge Wood, Big Talk

Dax Shepard, Stephen Moyer, Bush

John Stamos, Ashley Benson, Owl City

Kyra Sedgwick, Jay Forry, Theophilus London

Roseanne Barr, Aaron Paul, Viva Brother

Shia LaBeouf, Aaron Rogers, 311

Kevin Nealon, Dave Salmoni, Parachute

Jason Bateman, Dhani Jones, Hannibal Buress

Louis C.K., "Bachelorette" Ashley Hebert, Missy Peregrym, Steel Magnolia

Rosario Dawson, Michael Angarano, Jill Scott

Molly Shannon, Tim Tebow, Matt Nathanson

Eva Mendes, Jim Florentine, Pitbull

Owen Wilson, Adam Levine, Panic! at the Disco

Cedric the Entertainer, Ray Kurzweil, Breathe Carolina

Gordon Ramsay, Mike O'Malley, Hanson

Sarah Ferguson, Ryan Lee, Ice Cube

Elle Fanning, John Henson, Gruff Rhys

Kathy Griffin, J.J. Abrams, Friendly Fires

Katie Couric & Basketball player Glen Davis

Paris Hilton, "Bachelorette" Ashley Hebert, National Spelling Bee Champion Sukanya Roy, Sara Bareilles

Jason Sudeikis, Piers Morgan, Lykke Li

Don Rickles

Carson Daly, Flavor Flav, I See Stars

Christina Aguilera, Mike Tyson, Big Sean

Jesse Tyler Ferguson, Sarah Vowell, Maybach Music Group featuring Rick Ross

"Dancing with the Stars" winners Hines Ward & Kym Johnson, Taylor Lautner, Britney Spears

Wanda Sykes, "Bachelorette" Ashley Hebert, Foster the People

Khloe Kardashian Odom, "Science Bob" Pflugfelder

Albert Brooks, Chaz Bono, Rammstein

Topher Grace, Adam Carolla, Christina Perri

Kate Hudson, Windell Middlebrooks, Raphael Saadiq

Chris O'Donnell, Ginnifer Goodwin, Zac Brown Band

Nathan Fillion, "Dancing with the Stars" castoff Romeo, Calle 13

Rob Lowe, Ty Pennington, Wiz Khalifa

Chris Hemsworth, Adam Pally, Calexico

Kenneth Branagh, Ellie Kemper, the 2011 National School Scrabble Champions

Anthony Hopkins, Andre Agassi, "Dancing with the Stars" castoff Kendra Wilkinson-Baskett

Rene Russo, Kristin Gore, k.d. lang

Sofia Vergara, Manny Pacquiao, the Airborne Toxic Event

Larry King, Jaimie Alexander, Augustana

Mark Ruffalo, Jamie Oliver, "Dancing with the Stars" castoff Chris Jericho, Robbie Robertson

Martin Short, Kat Dennings, Alter Bridge

Christoph Waltz, Jessica Capshaw, Phantogram

Robert Pattinson, Shailene Woodley, Lenka

Dwayne Johnson, the latest "Dancing with the Stars" castoff, Sammy Hagar, the Belle Brigade

Courteney Cox, Gary Busey, Jessie J

Tom Arnold, Alison Brie, Francis & the Lights

Eva Longoria, Patrick Warburton, Robyn

Emma Roberts, Morgan Spurlock, "Dancing with the Stars" castoff Sugar Ray Leonard, Jenny and Johnny

David Arquette, Mike Birbiglia, Asking Alexandria

Vin Diesel, Neve Campbell, Ellie Goulding

Norm MacDonald, Elisha Cuthbert, Funeral Party

Christian Slater, Dr. Drew Pinsky, "Dancing With the Stars" castoff Wendy Williams, the Decemberists

Katie Holmes, Dana Delany, Bad Religion

David Beckham, Wes Craven, Sum 41

Danny McBride, Sara Ramirez, Duran Duran

Johnny Knoxville, "Dancing with the Stars" castoff Mike Catherwood, Britney Spears

Sharon Osbourne, Bruno Tonioli, the Sounds

Penelope Cruz, Paul Iacono, Oh Land

Jake Gyllenhaal, Jerry Weintraub, Quinn Sullivan

Rainn Wilson, Abbie Cornish, the Gaslight Anthem

Liv Tyler, Mark Cuban, Charlie Sheen, Brett Dennen

Matthew McConaughey, Jena Malone, Young Dubliners

Kristen Wiig, Adam Scott, the Wombats

Jane Lynch, David Boreanaz, Avril Lavigne

Ryan Phillippe, new "Bachelorette" Ashley Hebert, Ron Sexsmith

Howard Stern, Michael Franti and Spearhead

Amanda Seyfried, Nick Offerman, Henry Wolfe

Emily Blunt, Max Irons, Aaron Lewis

Bill Maher, Esperanza Spalding

Owen Wilson, Kelly Ripa, Adele

Nancy Grace, Twilight Singers

Cameron Diaz, Henry Winkler, Cake

Jason Sudeikis, Blake Griffin, Keri Hilson

Javier Bardem, Flavor Flav, Stone Sour

Jeremy Renner, Eric Stonestreet, Black Dub

Martin Lawrence, Dianna Agron, Jewel

Justin Bieber, Travis Barker featuring Game and Swizz Beats

Adam Sandler, Bobby Flay, Ke$ha

Matthew Perry, Morena Baccarin, Pitbull

Dr. Phil McGraw, Amy Sedaris, Nelly

Kim Kardashian, Alex Trebek, One eskimO

Josh Brolin, Camille Grammer, Tinie Tempah

Jamie Foxx, Sarah Shahi

Julianna Margulies, Matthew Bomer, the JaneDear Girls

Ryan Seacrest, Melissa Leo, Cage the Elephant

Amy Poehler, Martha Plimpton, Cold War Kids

Anthony Hopkins, Hailee Steinfeld, Delta Spirit

Cory Monteith, Joan Rivers, the Script

James McAvoy, Jim Sturgess, K.T. Tunstall

Ryan Gosling, Kourtney Kardashian, Ra Ra Riot

Don Rickles, Wilmer Valderrama, New Politics

Randy Jackson, Jennifer Lawrence, Andrew Norelli

Guest director Michel Gondry, Seth Rogen, Elle Fanning, the Damned Things

Meryl Streep, Stephen Merchant

Randy Jackson, Dermot Mulroney, Will Hoge

Don Cheadle, David Cross, Boyz II Men

Tracy Morgan, tUnE-yArDs

Octavia Spencer, Lloyd

Matt LeBlanc, Julie Benz, Michael Carbonaro