Cast
David Wain — Narrator
Michael Showalter — Coop/Alan Shemper
Marguerite Moreau — Katie
Michael Ian Black — McKinley
Paul Rudd — Andy
Christopher Meloni — Gene
Molly Shannon — Gail von Kleinenstein
Ken Marino — Victor Kulak
Joe Lo Truglio — Neil
Amy Poehler — Susie
Samm Levine — Arty

And special surprise guest understudies:
Busy Philipps — Beth (originally played by Janeane Garofalo)
David Cross — Henry Newman (originally played by David Hyde Pierce)
Joshua Malina — J.J. (originally played by Zak Orth)
Colin Hanks — Gary (originally played by A.D. Miles)
Marc Evan Jackson — Ben (originally played by Bradley Cooper)
Bruce McCulloch — Aaron (originally played by Gideon Jacobs)
Jessi Klein — Abby Bernstein (originally played by Marisa Ryan)
Gillian Jacobs — Lindsay (originally played by Elizabeth Banks)
John Hodgman — Keith – Caped Boy (originally played by Gabriel Millman)
Mark Gagliardi — Steve (originally played by Kevin Sussman)
Craig Cackowski — Mork Guy and Moose
Hal Lublin — Melvin – Medieval Kid
Annie Savage — Mallrat Girl/Cure Girl and Godspell Girl
Zandy Hartig — Nurse Nancy (originally played by Nina Hellman)
Andy Richter — Ron von Kleinenstein (originally played by Judah Friedlander)
Bobcat Goldthwait — Can of Vegetables (originally played by Jon Benjamin)

(via)

DID ANYONE GO TO THIS EPIC GATHERING OF AMAZING PEOPLE???