Ron Howard, Nicole "Snooki" Polizzi, Sick Puppies

Queen Latifah, Gustavo Dudamel, Jazmine Sullivan

Jamie Foxx, Leighton Meester

Hilary Swank, Jesse Eisenberg, Los Lobos

Jim Parsons, Hailee Steinfeld, Lukas Nelson

Randy Jackson, Jennifer Lopez, Ryan Seacrest, Steven Tyler, Dan Ahdoot, Diane Birch

Bill Maher, Cam Newton, the Duke Spirit

Seth Rogen, Brady Barr, Bettye Lavette

Cameron Diaz, Eric Stonestreet, the Civil Wars

Michael Douglas, Julie Scardina, Randy Rogers Band

Gordon Ramsay, Kathleen Madigan, Maroon 5

Ashton Kutcher, Aubrey Plaza, Neon Trees

Amy Poehler, Mike "The Situation" Sorrentino, Grace Potter & the Nocturnals

Ben Affleck, the Decemberists

Kathie Lee Gifford & Hoda Kotb, Armie Hammer, Hayes Carll

Dana Carvey, Maggie Q, Lizz Wright

Jason Statham, Melissa McCarthy, White Lies

Annette Bening, Frank Caliendo, Amos Lee

Kathy Bates, Brad Womack, Billy Currington

Justin Bieber, Jay Mohr, the Band Perry

Adam Sandler, Larry the Cable Guy, Esperanza Spalding

Helena Bonham Carter, Timothy Olyphant, One eskimO

Jesse Eisenberg, Jennifer Lawrence, Ryan Bingham

Jeff Bridges, Dianna Agron, Bobby Long

Hugh Laurie, Hailee Steinfeld, Finesse Mitchell

Mark Wahlberg, Lachlan Patterson, James Blunt

Javier Bardem, Paula Abdul, Merle Haggard

Matt LeBlanc, Clay Matthews, Ricky Martin

Rob Lowe, Amber Riley, Nicki Minaj

Kathy Griffin, Gayle King, the Black Keys

Lady Gaga, Sofia Vergara, John Legend

Liam Neeson, Dave Salmoni, Gretchen Wilson

Charles Barkley, Jenni "JWoww" Farley, Red

Jenna Fischer, Abigail Breslin, Miguel

Mark Harmon, Dwight Howard, 30 Seconds to Mars

The Tonight Show with Jay Leno Season 19 Episode 36

Owen Wilson, Rachel Maddow, Anberlin

Randy Jackson, Nick Swardson, Travie McCoy

Meredith Vieira, DJ Pauly D, Hanson

Emily Blunt, Jackson Murphy, Chris Medina

Christina Appelgate, John Fulton, Michael Franti

Matt Damon, Betty White, Cake

Simon Cowell, Jeff Gordon, Travis Barker

Jerry Seinfeld, Bailee Madison, Darlene Love

Aaron Eckhart, Christie Brinkley, Thompson Square

Jane Lynch, Chris Matthews, Avril Lavigne

Wanda Sykes, Simon Pegg, Juanes

Matthew McConaughey, Rizwan Manji, Michael Kosta

Rainn Wilson, "Epic Meal Time" with Harley Morenstein & Sterling Toth, Serj Tankian

Robert Pattinson, Whitney Cummings, Alice Cooper

Zachary Levi, Lisa Lampanelli, Raphael Saadiq

Julie Scardina, Rebecca Black, Duran Duran

Carol Burnett, Jason Ritter, Keith Urban

Kirstie Alley, Jon "Bones" Jones, Peter, Bjorn & John

Jennifer Hudson, William H. Macy

Russell Brand, Lorraine Nicholson, Los Lonely Boys

Howie Mandel, Zachary Gordon, Dierks Bentley

Helen Hunt, Sammy Hagar, Good Charlotte

Kourtney & Kim Kardashian, Fareed Zakaria, Mary Mary

Vin Diesel, Ashley Tisdale, Scissor Sisters

Tracy Morgan, Neve Campbell, Augustana

Dwayne Johnson, Bethany Hamilton, Fitz & the Tantrums

Matthew Morrison, Carrie Underwood

Emma Roberts, Gary Busey, Jeff Beck with Imelda May

David Arquette, Ben Bailey, Far East Movement

Jamie Foxx, k.d. lang

Kristen Bell, Austin "Chumlee" Russell

Jessie J

Tyler Perry, Kendra Wilkinson, Bright Eyes

John Travolta, Eliza Doolittle

Christina Aguilera, Paul Reiser, Alison Krauss & Union Station featuring Jerry Douglas

Lindsay Lohan, Jillian Michaels, the Airborne Toxic Event

Rene Russo, Kevin Hart, Buddy Guy

Chelsea Handler, Judd Apatow, OK Go

Rob Lowe, Moby

Paul Walker, Donny & Marie Osmond

Penelope Cruz, Ricky Martin

Kate Hudson, Chris Hemsworth, Sergio Mendes with Siedah Garrett

Wanda Sykes, Ralph Macchio, Priscilla Ahn

Steven Tyler, Aubrey Plaza, the Civil Wars

Jennifer Lopez, Chris Colfer, BC Jean

Julie Scardina, Ginnifer Goodwin, Def Leppard

Dick Van Dyke, Khloe Kardashian & Lamar Odom, Steve Earle

Norm Macdonald

Jodie Foster, Ken Jeong, Rodrigo y Gabriela

Eva Mendes, storm chaser Reed Timmer, Tedeschi Trucks Band

Ryan Seacrest, Jordana Brewster, TV on the Radio

Ed Helms, Chelsea Kane, Iron & Wine

Jack Black, Mike Huckabee, Parachute

Kirstie Alley, Erik Rivera, Il Volo

Dustin Hoffman, Meghan McCain, the Script

Meredith Vieira, Demetri Martin, Ben Harper

Chaz Bono, Brady Barr, Foster the People

Piers Morgan, Rico Rodriguez, Scott Weiland

Paris Hilton, Dhani Jones, INXS with Pat Monahan

Katie Couric, Cee-Lo Green

Kevin Bacon, Bethenny Frankel, OneRepublic

Jada Pinkett Smith, Elle Fanning, Lenka

Jim Carrey, Selena Gomez, Tinie Tempah

Bill Cosby, Kris & Bruce Jenner, Neon Trees

Adam Levine, Ziggy Marley

Kim Kardashian, Lior Suchard, Randy Travis with Josh Turner

Blake Lively, Blake Shelton, Scotty McCreery

Larry David, Pitbull with Ne-Yo

Josh Duhamel, Jill Scott

Bono & the Edge, Larry the Cable Guy, a performance from

Rosario Dawson, Marc Anthony, Jackie Evancho

Louis C.K., Richard Engel, Raphael Saadiq

Justin Timberlake, Kevin Hart, the Antlers

David Spade, Tom Papa, Plain White T's

Jim Carrey, Selena Gomez, Tinie Tempah

Blake Lively, Blake Shelton, Scotty McCreery

Larry David, Ashley Hebert, Pitbull featuring Ne-Yo

Kirstie Alley, Comic Erik Rivera

Lisa Kudrow, Billy Gardell, Natasha Bedingfield

Julie Scardina; Mary-Louise Parker; Billy Ray Cyrus

Kevin James, The Voice winner Javier Colon

Howie Mandel, David Feherty, Joss Stone

Seth Meyers, Marjorie Johnson, Barry Manilow

Craig Ferguson, Rose Byrne

Don Rickles, Bristol Palin, Colbie Caillat

Bryan Cranston, Nancy Grace, Shaggy

Neil Patrick Harris, Buddy Valastro, Imelda May

Jenna Fischer, Ben Bailey, 3 Doors Down

Daniel Craig, Gavin DeGraw

Emma Stone, Adam Carolla, Rickey Minor, Grace Potter, Charles Bradley, Sharon Jones

Dolly Parton, Ben Bailey

Jessica Alba, Sue Johanson, Gomez

Shaun White, Olivia Wilde, Train

Chris Tucker, Skipper Bivins & Trent Jackson, Vanessa Carlton

Matt LeBlanc, Freida Pinto, Stevie Nicks

Gillian Anderson, Aziz Ansari, Kelly Rowland

Ryan Reynolds, Sheryl Crow, Matt Nathanson

Katie Holmes, Novak Djokovic, Mat Kearney

Jeremy Piven, Kelly Osbourne

Roseanne Barr, Jason Momoa, Lykke Li

Dennis Miller, Dennis Rodman, Rye Rye featuring Robyn

Gordon Ramsay, Bryce Dallas Howard, Panic! at the Disco

Jesse Eisenberg, Mike ''The Situation'' Sorrentino

Joel McHale, Viola Davis, Ximena Sarinana

Sam Worthington, Bailee Madison, The Game

Jane Fonda, Elizabeth Banks, Mana

Julie Scardina, David Koechner, Cake

Jeff Bridges, Nicole

Allison Janney, Jay Mohr, OK Go

Heidi Klum, Kevin Smith, Fitz and the Tantrums

Dick Cheney, Carrot Top, Andy Grammer

Wanda Sykes, Nick Swardson, Roger Daltrey

Kristin Chenoweth, Chris Colfer

Will Arnett, Tinie Tempah

Bill Maher, Octavia Spencer, Alice Cooper

Christina Applegate, Pauly D, Glen Campbell

Ellen DeGeneres, Bob Harper, Cobra Starship

Jane Lynch, Demetri Martin, Needtobreathe

Kevin Hart, Charlie Sheen, LMFAO

Jason Statham, Michele Bachmann, Lady Antebellum

Simon Cowell, Natasha Leggero, Selena Gomez

Gerard Butler, Whitney Cummings, Kelly Clarkson

Amy Poehler, Joseph Gordon-Levitt, the Kooks

Jamie Foxx, Michelle Monaghan, Bush

Hugh Jackman, Maya Rudolph, Tony Bennett

Ryan Gosling, Pauley Perrette, Arctic Monkeys

Lauren Graham, Seth MacFarlane

Ed Helms, Lisa Hannigan

Albert Brooks, Deena Nicole Coretese, TV on the Radio

Hugh Laurie, Chaz Bono, the Airborne Toxic Event

Evangeline Lilly, Magic Johnson, Jo Koy

Kim Kardashian, Kris Humphries, Kenny Wormald, LeAnn Rimes

Tim Allen, Theresa Caputo, Scotty McCreery

Jack Black, Steve Martin, Owen Wilson, Aubrey Plaza, Blondie

David Arquette, Darrell & Brandon Sheets, Puddle of Mudd

Aaron Eckhart, Julianne Hough, Amos Lee

Julie Bowen, Dave Salmoni, Imelda May

Zooey Deschanel, J.R. Martinez, Fountains of Wayne

Zachary Levi, Gloria Estefan

Terry Bradshaw, Rowan Atkinson, Game

Jonah Hill, Paula Deen, Chris Isaak

President Barack Obama

Amanda Seyfried, John Cho & Kal Penn, Patrick Stump

Chelsea Handler, Chris D'Elia, the Original 7ven

Adam Sandler, Drew Manning, Awolnation

Justin Bieber, David Freese, Lloyd

Eddie Murphy, Robyn

Taylor Lautner, Martha Stewart, Daughtry

Kristen Stewart, Dave Attell, Joe Jonas

Miss Piggy, Mickey Rourke, Mute Math

Ellen Barkin, Henry Cavill, Cirque du Soleil

Jason Segel, Kris Jenner, Lyle Lovett

Kelsey Grammer, Andrea Bocelli

Whitney Cummings, Chris Matthews, Il Divo

Kermit the Frog, Ricki Lake

Amy Adams, Rocket City Rednecks, Miranda Lambert

Howie Mandel, Nicole "Snooki" Polizzi, Patrick Stump

Robin Williams, Vince Gill

Jimmy Fallon, Drew Brees, Gym Class Heroes

Jim Parsons, Meghan McCain, Tom Morello with Ben Harper

Dennis Miller, David & Sean La Vau, Javier Colon

Julie Scardina, Dane Cook, Hot Chelle Rae

Chelsea Handler, Dwight Howard, Gloriana

Damon Wayans Jr., She & Him

Kathy Bates, Jay Mohr, Switchfoot

Bill Cosby, Raini Rodriguez, Iron & Wine

Melissa McCarthy, Gov. Rick Perry, T-Pain

Hilary Swank, Mike 'The Situation' Sorrentino, Dia Frampton'

Robert Downey Jr., Abigail Breslin, Alison Krauss & Union Station

Katherine Heigl, J.B. Smoove, Taio Cruz

Lea Michele, Adam Carolla, Neil Diamond

Katie Couric, Chris D'Elia, Blake Shelton

Bill O'Reilly, Jackie Evancho

Charlize Theron, Kevin Hart, Foster the People

Dana Carvey, Jason Reitman, Lenny Kravitz

Louis C.K., Common

Al Michaels & Cris Collinsworth, Elle Fanning, Robin Thicke

Rep. Ron Paul, Chris Cornell

Sandra Bullock, Diablo Cody, Pink Martini

Charles Barkley, Berenice Bejo, Amber Riley

Thomas Haden Church,

Jonah Hill, Chris Paul, Il Volo

Terry Bradshaw, Bailee Madison, Chris Isaak