Episode 1
Episode 18
Nicollette Sheridan/The All-American Rejects
George Clooney/Kiefer Sutherland/T.I.
Amy Poehler, James Morrison
Joey Fatone, O.A.R.
Ted Danson, Ernie Bjorkman
Kevin Nealon, Chris Harrison
Alyson Hannigan, Brandon Wilson
Heidi Klum, Justin Long, Marco Borges
Josh Brolin, Pink with Butch Walker
Penelope Cruz, Dylan and Cole Sprouse, Q-Tip
Jennifer Aniston, Stevie Wonder
John Mayer, Josh Groban, Lady Antebellum, Chester Pitts, Ephraim Salaam
Amy Brenneman, Jason Mraz and Colbie Caillat
Mel B, Eric Dane, Robin Tunney, Melinda Doolittle
Steve Harvey, Kurt Warner, Dr. Neil Shaw
John Legend, Jerry O'Connell
Simon Baker, Miranda Cosgrove
The Jonas Brothers, Mel B
Naomi Watts, Lily Allen
Jeff Probst, Nick Carter
George Lopez, Bar Refaeli
Meredith Vieira, Olivia Wilde
Richard Simmons, Serena Williams, Raphael Saadiq
Denise Richards, Chyler Leigh, Fabio Viviani
Mario Lopez, the Bird and the Bee
David Arquette, Fall Out Boy
Neil Patrick Harris, Kaley Cuoco
Judge Judy Sheindlin, Bret Michaels, Matt Nathanson
Eric McCormack, Chris Harrison, Anthony LaPaglia, the Fray
"The Bachelor" runner-up Melissa Rycroft, Kym Douglas
Jason Mesnick and Molly Malaney, Steve Spangler
Paris Hilton
Carla Gugino, Sean "Diddy" Combs, Taylor Hicks
Carol Burnett, Taylor Hicks
Felicity Huffman, Rascal Flatts
Dwayne "The Rock" Johnson, Elle Fanning
Portia de Rossi, "American Idol" castoffs Jorge Nunez and Jasmine Murray
Julia Louis-Dreyfus, Andy Samberg
Zach Braff, Jenna Fischer
Anderson Cooper, Katy Perry
Paul Rudd, Gavin Rossdale, 7-year-old golfer Brett Sodetz
Noah Wyle, "American Idol" castoff Alexis Grace
Kara DioGuardi, M.C. Hammer
John Stamos, Emily Blunt
Jennifer Hudson
Reese Witherspoon, Bobby Flay
David Spade, Gilles Marini and Cheryl Burke
Halle Berry, Flo Rida
Christina Applegate, Keith Urban
Howie Mandel, Ben Mckenzie
Marilu Henner, Lil' Kim and Derek Hough, Martina McBride
Patricia Arquette, Wayne Hoffman, "Dancing With the Stars" castoff David Alan Grier, Rascal Flatts
Jenny McCarthy, Mary McCormack, Natasha Bedingfield
Zac Efron, Demi Lovato
Jessica Lange, Melissa Rycroft and Tony Dovolani, Ludacris and Jesse McCartney
Drew Barrymore, Barry Watson, the Pussycat Dolls
Leslie Mann, Rashida Jones, Pussycat Dolls
Jimmy Kimmel, Marilyn Milian, Brett Dennen, 7-year-old break-dancer Angelo Baligad
Jennifer Love Hewitt, Chicago
Lindsay Lohan, Alec Greven, Prince
Matthew Perry, Leighton Meester
Kristin Chenoweth, "American Idol" castoffs Anoop Desai and Lil Rounds
Kate Walsh, Dierks Bentley, child solar-system expert Brandt Bickford
Michael Douglas, Faryl Smith
Ryan Reynolds, 7-year-old piano prodigy Emily Bear
Matthew McConaughey
Heidi Klum, Annie Duke, "American Idol" castoff Matt Giraud
Simon Cowell, Zachary Quinto, the Black Eyed Peas
Hugh Jackman, Chris Pine
Vanessa Hudgens, 11-year-old sport stacker Steven Purugganan, Kym Douglas
Ryan Seacrest, Alison Sweeney
Jon Cryer, "American Idol" castoff Allison Iraheta, Alison Sweeney
Matthew Fox, Julianne Moore, Lady GaGa
Jay Leno, Ciara
Anderson Cooper, Kelly Clarkson
Ewan McGregor, the winner of "The Biggest Loser", Pink
Jamie Foxx, Marisa Miller, piano prodigy Umi Garrett
George Lopez, No Doubt
Ben Stiller, David Cook
Kevin Nealon, Tamar Geller, Michael Johns
Queen Latifah, Wayne Dyer, Rob Thomas
Steve Martin
Mandy Moore, Kris Allen
Jessica Biel, Kathy Freston, Kellie Pickler
