John Krasinski, Robin Thicke, Shaheen Jafargholi

Craig Ferguson, Zoe Saldana

Paris Hilton, Lewis Blackwell

John Mayer, So You Think You Can Dance

Ray Romano, Marie Tillman

Selena Gomez & the Scene, chef Roberto Martin

Steve Harvey, Mindy Kaling

Howie Mandel, Marie Osmond

Clint Eastwood, Overtone

Zach Braff, Allison Iraheta

Zach Braff, Allison Iraheta

Tobey Maguire, Cirque du Soleil's "Kooza"

Matt Dillon, Ashley Greene, Tia Torres

Adam Lambert, Marisa Miller

Lady Gaga, Kym Douglas

Sandra Bullock

Kris Allen, Penelope Cruz

Bon Jovi, Kelly Osbourne & Louis van Amstel

Robert Pattinson, 13-year-old violinist Justus Rivera

Simon Baker, Leona Lewis, Andre Agassi

Carrie Underwood, Kellan Lutz

Dwayne Johnson, Brian Williams, Rhap Salazar

Dakota Fanning, Diddy

Ryan Seacrest

Harry Connick Jr., Paula Patton

John Travolta, Ella Bleu Travolta

Jenny McCarthy, Shemar Moore

George Lopez, Robin Wright Penn

Pamela Anderson, young inventors

Amy Poehler, Fran Drescher

Mariah Carey, Jonathan Safran Foer

Mo'Nique, Justin Bieber, Abby Rike

Jim Carrey, Faith Hill

Alicia Keys, Rick Springfield, Science Guy Steve Spangler

Taylor Swift, Tim McGraw

Katie Couric, Kate Gosselin, Gabourey "Gabby" Sidibe

Jimmy Kimmel, Deepak Chopra

Hilary Swank, Jay Sean

Alyson Hannigan, Mya & Dmitry Chaplin

David Spade, John C. Reilly, Mika

Mario Lopez, chef Roberto Martin

Lauren Graham, OneRepublic

Hayden Panettiere, Angel Taylor, Aaron Carter

Marcia Cross, Dylan Walsh

Taye Diggs, Wolfgang Puck

Alison Sweeney, the Script

Jimmy Smits, T.R. Knight, Daughtry

Vince Vaughn, Pete Yorn & Scarlett Johansson

Jason Bateman, Judy Shepard

Clive Owen, Joely Fisher, the Backstreet Boys

Ellen Page, Kevin Nealon, Michael Franti & Spearhead

Rob Lowe, Juliette Lewis, Miranda Lambert

Julia Louis-Dreyfus, Jason Schwartzman, Melissa Joan Hart

Felicity Huffman, Roger Daltrey

Kate Walsh, Melissa Sandvig & Ade Obayomi

Heidi Klum, Brad Paisley

Drew Barrymore

Rebecca Romijn

Patricia Arquette, Tom DeLay & Cheryl Burke

Christina Applegate, Dave Annable, Noisettes

Courteney Cox, Ricky Gervais, Jessie James

Jennifer Garner, Joe Wong, Paolo Nutini

Jennifer Love Hewitt, Kelly Osbourne

Neil Patrick Harris, Anna Faris, Colbie Caillat

Ted Danson, Anna Torv, Maxwell

Jennifer Aniston, the Dave Matthews Band

Queen Latifah

Sharon Osbourne, Rumer Willis

Katherine Heigl, Nick Cannon

Kate Beckinsale, Jillian Harris & Ed Swiderski, Pitbull

Antonio Banderas, Lisa Wu Hartwell, NeNe Leakes

David Beckham, Lady Gaga

Jessica Biel, Kathy Freston, Kellie Pickler

Mandy Moore, Kris Allen

Steve Martin

Queen Latifah, Wayne Dyer, Rob Thomas

Kevin Nealon, Tamar Geller, Michael Johns

Ben Stiller, David Cook

George Lopez, No Doubt

Jamie Foxx, Marisa Miller, piano prodigy Umi Garrett

Ewan McGregor, the winner of "The Biggest Loser", Pink

Anderson Cooper, Kelly Clarkson

Jay Leno, Ciara

Matthew Fox, Julianne Moore, Lady GaGa

Jon Cryer, Allison Iraheta, Alison Sweeney

Ryan Seacrest, Alison Sweeney

Vanessa Hudgens, Steven Purugganan, Kym Douglas

Hugh Jackman, Chris Pine

Simon Cowell, Zachary Quinto, the Black Eyed Peas

Heidi Klum, Annie Duke, "American Idol" castoff Matt Giraud

Matthew McConaughey

Ryan Reynolds, 7-year-old piano prodigy Emily Bear

Michael Douglas, Faryl Smith

Kate Walsh, Dierks Bentley, Brandt Bickford

Kristin Chenoweth, Anoop Desai and Lil Rounds

Matthew Perry, Leighton Meester

Lindsay Lohan, Alec Greven, Prince

Jennifer Love Hewitt, Chicago

Jimmy Kimmel, Marilyn Milian, Brett Dennen

Leslie Mann, Rashida Jones, Pussycat Dolls

Drew Barrymore, Barry Watson, the Pussycat Dolls

Jessica Lange, Melissa Rycroft, Ludacris

Zac Efron, Demi Lovato

Jenny McCarthy, Mary McCormack, Natasha Bedingfield

Patricia Arquette, Wayne Hoffman, Rascal Flatts

Marilu Henner, Lil' Kim and Derek Hough, Martina McBride

Howie Mandel, Ben Mckenzie

Christina Applegate, Keith Urban

Halle Berry, Flo Rida

David Spade, Gilles Marini and Cheryl Burke

Reese Witherspoon, Bobby Flay

Jennifer Hudson

John Stamos, Emily Blunt

Kara DioGuardi, M.C. Hammer

Noah Wyle, "American Idol" castoff Alexis Grace

Paul Rudd, Gavin Rossdale, 7-year-old golfer Brett Sodetz

Anderson Cooper, Katy Perry

Zach Braff, Jenna Fischer

Julia Louis-Dreyfus, Andy Samberg

Portia de Rossi, Jorge Nunez and Jasmine Murray

Dwayne "The Rock" Johnson, Elle Fanning

Felicity Huffman, Rascal Flatts

Carol Burnett, Taylor Hicks

Carla Gugino, Sean "Diddy" Combs, Taylor Hicks

Paris Hilton

Jason Mesnick and Molly Malaney, Steve Spangler

"The Bachelor" runner-up Melissa Rycroft, Kym Douglas

Eric McCormack, Chris Harrison, Anthony LaPaglia, the Fray

Judge Judy Sheindlin, Bret Michaels, Matt Nathanson

Neil Patrick Harris, Kaley Cuoco

David Arquette, Fall Out Boy

Mario Lopez, the Bird and the Bee

Denise Richards, Chyler Leigh, Fabio Viviani

Richard Simmons, Serena Williams, Raphael Saadiq

Meredith Vieira, Olivia Wilde

George Lopez, Bar Refaeli

Jeff Probst, Nick Carter

Naomi Watts, Lily Allen

The Jonas Brothers, Mel B

Simon Baker, Miranda Cosgrove

John Legend, Jerry O'Connell

Steve Harvey, Kurt Warner, Dr. Neil Shaw

Mel B, Eric Dane, Robin Tunney, Melinda Doolittle

Amy Brenneman, Jason Mraz and Colbie Caillat

John Mayer, Josh Groban, Lady Antebellum, Chester Pitts

Jennifer Aniston, Stevie Wonder

Drew Barrymore, Taraji P. Henson

Penelope Cruz, Dylan and Cole Sprouse, Q-Tip

Josh Brolin, Pink with Butch Walker

Heidi Klum, Justin Long, Marco Borges

Alyson Hannigan, Brandon Wilson

Kevin Nealon, Chris Harrison

Ted Danson, Ernie Bjorkman

Joey Fatone, O.A.R.

Amy Poehler, James Morrison

Kyra Sedgwick/Howie Mandel

Brendan Fraser/Emily Deschanel

Barack Obama/Jimmy Fallon/Kelli Williams

Beyonce

George Clooney/Kiefer Sutherland/T.I.

Nicollette Sheridan/The All-American Rejects

Chandra Wilson/Tione Johnson

Dustin Hoffman/Brandt Bickford

Randy Jackson/Dr. Wayne Dyer/Michelle Aguilar

Wolf Blitzer

Clint Eastwood/Jason Mesnick

Anne Hathaway

Wanda Sykes, 5-year-old actress Kylie Kim

Akon

Marisa Tomei/Foreigner

Helen Mirren, 8-year-old pianist Emily Bear, Kesha

Eva Mendes/Kevin McKidd

Christian Slater, Rickie Lee Jones & Ben Harper