Episode 1: Episode 1

Episode 18: Episode 18

Episode 84: Nicollette Sheridan/The All-American Rejects

Episode 85: George Clooney/Kiefer Sutherland/T.I.

Episode 90: Amy Poehler, James Morrison

Episode 91: Joey Fatone, O.A.R.

Episode 92: Ted Danson, Ernie Bjorkman

Episode 93: Kevin Nealon, Chris Harrison

Episode 94: Alyson Hannigan, Brandon Wilson

Episode 95: Heidi Klum, Justin Long, Marco Borges

Episode 96: Josh Brolin, Pink with Butch Walker

Episode 97: Penelope Cruz, Dylan and Cole Sprouse, Q-Tip

Episode 99: Jennifer Aniston, Stevie Wonder

Episode 100: John Mayer, Josh Groban, Lady Antebellum, Chester Pitts, Ephraim Salaam

Episode 101: Amy Brenneman, Jason Mraz and Colbie Caillat

Episode 102: Mel B, Eric Dane, Robin Tunney, Melinda Doolittle

Episode 103: Steve Harvey, Kurt Warner, Dr. Neil Shaw

Episode 104: John Legend, Jerry O'Connell

Episode 105: Simon Baker, Miranda Cosgrove

Episode 106: The Jonas Brothers, Mel B

Episode 107: Naomi Watts, Lily Allen

Episode 108: Jeff Probst, Nick Carter

Episode 109: George Lopez, Bar Refaeli

Episode 110: Meredith Vieira, Olivia Wilde

Episode 111: Richard Simmons, Serena Williams, Raphael Saadiq

Episode 112: Denise Richards, Chyler Leigh, Fabio Viviani

Episode 113: Mario Lopez, the Bird and the Bee

Episode 114: David Arquette, Fall Out Boy

Episode 115: Neil Patrick Harris, Kaley Cuoco

Episode 116: Judge Judy Sheindlin, Bret Michaels, Matt Nathanson

Episode 117: Eric McCormack, Chris Harrison, Anthony LaPaglia, the Fray

Episode 118: "The Bachelor" runner-up Melissa Rycroft, Kym Douglas

Episode 119: Jason Mesnick and Molly Malaney, Steve Spangler

Episode 120: Paris Hilton

Episode 121: Carla Gugino, Sean "Diddy" Combs, Taylor Hicks

Episode 122: Carol Burnett, Taylor Hicks

Episode 123: Felicity Huffman, Rascal Flatts

Episode 124: Dwayne "The Rock" Johnson, Elle Fanning

Episode 125: Portia de Rossi, "American Idol" castoffs Jorge Nunez and Jasmine Murray

Episode 126: Julia Louis-Dreyfus, Andy Samberg

Episode 127: Zach Braff, Jenna Fischer

Episode 128: Anderson Cooper, Katy Perry

Episode 129: Paul Rudd, Gavin Rossdale, 7-year-old golfer Brett Sodetz

Episode 130: Noah Wyle, "American Idol" castoff Alexis Grace

Episode 131: Kara DioGuardi, M.C. Hammer

Episode 132: John Stamos, Emily Blunt

Episode 133: Jennifer Hudson

Episode 134: Reese Witherspoon, Bobby Flay

Episode 135: David Spade, Gilles Marini and Cheryl Burke

Episode 136: Halle Berry, Flo Rida

Episode 137: Christina Applegate, Keith Urban

Episode 138: Howie Mandel, Ben McKenzie

Episode 139: Marilu Henner, Lil' Kim and Derek Hough, Martina McBride

Episode 140: Patricia Arquette, Wayne Hoffman, "Dancing With the Stars" castoff David Alan Grier, Rascal Flatts

Episode 141: Jenny McCarthy, Mary McCormack, Natasha Bedingfield

Episode 142: Zac Efron, Demi Lovato

Episode 143: Jessica Lange, Melissa Rycroft and Tony Dovolani, Ludacris and Jesse McCartney

Episode 144: Drew Barrymore, Barry Watson, the Pussycat Dolls

Episode 145: Leslie Mann, Rashida Jones, Pussycat Dolls

Episode 146: Jimmy Kimmel, Marilyn Milian, Brett Dennen, 7-year-old break-dancer Angelo Baligad

Episode 147: Jennifer Love Hewitt, Chicago

Episode 148: Lindsay Lohan, Alec Greven, Prince

Episode 149: Matthew Perry, Leighton Meester

Episode 150: Kristin Chenoweth, "American Idol" castoffs Anoop Desai and Lil Rounds

Episode 151: Kate Walsh, Dierks Bentley, child solar-system expert Brandt Bickford

Episode 152: Michael Douglas, Faryl Smith

Episode 153: Ryan Reynolds, 7-year-old piano prodigy Emily Bear

Episode 154: Matthew McConaughey

Episode 155: Heidi Klum, Annie Duke, "American Idol" castoff Matt Giraud

Episode 156: Simon Cowell, Zachary Quinto, the Black Eyed Peas

Episode 157: Hugh Jackman, Chris Pine

Episode 158: Vanessa Hudgens, 11-year-old sport stacker Steven Purugganan, Kym Douglas

Episode 159: Ryan Seacrest, Alison Sweeney

Episode 160: Jon Cryer, "American Idol" castoff Allison Iraheta, Alison Sweeney

Episode 161: Matthew Fox, Julianne Moore, Lady GaGa

Episode 162: Jay Leno, Ciara

Episode 163: Anderson Cooper, Kelly Clarkson

Episode 164: Ewan McGregor, the winner of "The Biggest Loser", Pink

Episode 165: Jamie Foxx, Marisa Miller, piano prodigy Umi Garrett

Episode 166: George Lopez, No Doubt

Episode 167: Ben Stiller, David Cook

Episode 168: Kevin Nealon, Tamar Geller, Michael Johns

Episode 169: Queen Latifah, Wayne Dyer, Rob Thomas

Episode 170: Steve Martin

Episode 171: Mandy Moore, Kris Allen

Episode 172: Jessica Biel, Kathy Freston, Kellie Pickler