Here's mine...
Eric Idle - appearing in a sketch where he argues (or at least tries to) with Oscar, in an allusion to the "Argument Sketch"
Harland Williams - I can see him appearing in a sketch with Cookie Monster, bellowing out "COOKIE" in the same manner as his way of saying "fudge".
Penn and Teller
Jennifer Coolidge
Amy Adams
Jerry Stiller
Cheryl Hines
Hugh Laurie
Cast of Family Guy - they had The Simpsons on the show once, so why not the Griffins? Just as long as they keep their humor clean, of course.
Lady Gaga
Jack Nicholson
"Weird Al" Yankovic
Jeff Dunham
Eddie Murphy
Dave Chappelle
Will Ferrell
Chris Kattan
Samuel L. Jackson
Mr. T
The GEICO Gecko
The old man from the Six Flags commercials
The Interrupter
Andy Richter
Sarah Silverman
Mary Louise Parker
U2
Danny Bonaduce
Gene Simmons
Jennifer Saunders
Dana Carvey
Heather Locklear
John Lithgow
Wayne Knight
Cast of 30 Rock - in a counting insert similar to "Fred, Get Me a 20"
The guy who played Napoleon Dynamite
Mel Brooks
Matthew Broderick
Ben Stein
Dick Van Dyke
Ed O'Neil
MC Hammer
William Shatner
Mike Myers as Austin Powers, demonstrating the word "dance" (yeah, baby!)
Christopher Walken
Jason Lee
Crista Flanagan
Borat
p)
Courtney Thorne-Smith --->
Angry Video Game Nerd
Quentin Tarantino
Larry the Cable Guy
ALF
Ben Stiller, with Owen Wilson
The guy who played Mini-Me in the Austin Powers movies
Elizabeth Hurley
Oh wait...there's absouletely no way we're gonna see half of the people on my list appear, all because of that
stupid controversy...
They'll probably stick to more "A-list" personalities like Feist or Jason Mraz or Jude Law (shudder)