Courteney Cox
Marsha Holloway
Spencer Breslin
Tucker Willams / Mega-Boy
Kevin Zegers
Connor Shepard / Concussion
Kate Mara
Summer Jones / Wonder
Michael Cassidy
Dylan West / Houdini
Ryan Whitney
Cindy Collins / Princess
Cornelia Guest
Cindy's Mom
Ashton Moio
Halloween Bully
Thomas F. Wilson
Dylan's Teacher
Danny McCarthy
Meaner Bully
David L. Lander
Wendy's Employee
Jane Hajduk
Researcher Taylor
Tommy Chang
Martial Arts Instructor
Tim Nasiopoulos
Large Agent
Deanna DeLisle
Cheerleader
Kendra Rose Montagna
Cheerleader
Aaron Abrams
Corporal Lipscombe (uncredited)
Stacey Alfano
Stefanie (uncredited)
Nick Baga
Fat Swimmer (uncredited)
Alexis Bledel
Ace (uncredited)
Darryl Dinn
Lab Researcher (uncredited)
Allison Gordon
Girl with Big Hair (uncredited)
Sadey Paige Nifong
Kid In Pool (uncredited)
Andrea Savo
Carmen / Big haired Latina (uncredited)