Gov. Ed Rendell

Geoffrey Canada

Atul Gawande

Dr. Ronald DePinho

Fen Montaigne

Chris Hughes

Bernard-Henri Levy

Kevin Spacey

Sherry Turkle

Cornel West

Ron Reagan Jr.

Chris Matthews

Charlie Rose

Amy Chua

Michael Waldman, Christine Yvette Lewis

Dr. Daryl Bem, Brian Greene

Samer Shehata, Dr. Paul Offit

Leslie Dach, Michael Lewis

Sean Kelly

Jane McGonigal

LCD Soundsystem

Christiane Amanpour, David Albright

Eric Foner

Jeffrey Leonard

Eugene Jarecki

Randi Weingarten, Bing West

Stephanie Coontz

Glenn Greenwald, Mike Huckabee

Michael Scheuer

Evan Osnos

Harry Connick Jr.

Mark W. Moffett

Joshua Foer

Dan Sinker

David Brooks

Reza Aslan

Steve Martin and the Steep Canyon Rangers

Ayman Mohyeldin

Nathan Myhrvold

Jody Williams

Michael Moore

Dr. Anthony Fauci

Tim Shriver

Piers Gibbon

Andrew Chaikin

James Franco

Sir David Tang

Jeff Greenfield

Jamie Hyneman and Adam Savage

Ray Kurzweil

Morgan Spurlock

Caroline Kennedy

Ron Paul

A.C. Grayling

Ice-T

Wade Graham

Francis Fukuyama

Rex Ryan

Amy Farrell

Bill James

Lupe Fiasco

Geoffrey Rush

Eric Greitens

John Bradshaw

Alison Klayman

Amy Kremer

Austan Goolsbee

Kareem Abdul-Jabbar

James Stewart

Robert Kennedy, Jr.

Salman Khan

Werner Herzog

Sugar Ray Leonard

Bre Pettis

Tom Ridge

Henry Kissinger

Janny Scott

Keith Olbermann

Bon Iver

Florence And The Machine

Talib Kweli

The Black Belles

Grover Norquist

Alexandra Pelosi

Gary Sinise

Timothy Garton Ash

Michael Shermer

Dan Savage

David McCullough

Jose Antonio Vargas

John Prendergast

David Carr

Michael Sandel

David Eagleman

Brian Cox

Mary (Missy) Cummings

Buddy Roemer

Tony Hsieh

Al Hunt

Robert Wittman

Anthony Bourdain

Nassir Ghaemi

The Cars

Elliot Ackerman

Gloria Steinem

Ambassador Susan Rice

STS-135 astronauts

Jeff Bridges

Kevin Mitnick

Gov. Tim Pawlenty

Robin Wright

Tom Brokaw

Diane Sawyer

Al Gore

Michael Moore

David Copperfield

Jeffrey Kluger

Daniel Yergin

Jeremy Ben-Ami

Radiohead

Melinda Gates

Ken Burns

Mark Cuban