- Cara Buono
- Joanne Schwartzbaum
- Robert Downey Sr.
- Baker
- Jonah Meyerson
- Henry Schwartzbaum
- Quinn Shephard
- Linda Schwartzbaum
- David Lansbury
- Brian Schwartzbaum
- Richard M. Davidson
- Doctor
- Lori Tan Chinn
- Mrs. Kim
- Laura Esterman
- Psychiatrist
- David Smilow
- Science Reporter
- Michael Clinton
- Farmer
- Isaach De Bankolé
- Abraham Conga
- Joseph McKenna
- Confessor
- Lori Braverman
- Woman Gambler
- Paul Lazar
- Larry
- Alberto Vazquez
- Jerry
- Tyagi Schwartz
- Rosselli
- Johann Carlo
- Frieda
- Ethan Crough
- Jack
- Susham Bedi
- Vegetarian
- Jimmy Gary Jr.
- Sam
- Kola Ogundiran
- Peter
- Sean Sutherland
- Tourist
- Joel de la Fuente
- Homeless Man / Alien
- Melissa Leo
- Miriam
- Peri Smilow
- News Reporter
- Rony Clanton
- Frank
- Robert Peters
- Steve Sanders
- Dwandra Nickole
- Admissions Person
- Peter Bartlett
- Curator
- Traci Parks
- Conservator
- Larry Block
- Brian's Dad
- Marcia Jean Kurtz
- Brian's Mom
- Sharon Wilkins
- Jill
- Ed Wheeler
- Guard
- Jay Oakerson
- Big Lab Assistant
- Gregory Korostishevsky
- Small Lab Assistant
- Kristen Schaal
- Information Librarian
- Dennis Albanese
- Gambler
