C-eh-n-eh-d-eh

TV Shows:
Degrassi
Instant Star
This Hour Has 22 Minutes
Royal Canadian Air Farce

Artists/Bands:
Sarah McLachlan
Alanis Morissette
Barenaked Ladies
Nickelback
Michael Buble
Default
Celine Dion

Actors:
Hayden Christensen
Brenden Fehr (Roswell)
Jim Carrey
Shawn Ashmore (X-men, or Animorphs if you're into old school Nickelodeon)
Matthew Perry
Alan Thicke
Michael J. Fox
Neve Campbell
Devon Sawa
Eugene Levy
Eric McCormack (Will & Grace)
Joshua Jackson
Kevin Zegers (Air Bud)
Jill Hennessy (Law & Order)
John Candy
Rachel McAdams (The Wedding Crashers, The Family Stone)
Elisha Cuthbert (The Girl Next Door)
Donald Sutherland (son Keifer was born in England)
Anna Paquin
William Shatner
Kristin Kreuk (Smallville)
Ryan Gosling
Rachel Blanchard (Clueless)
Brendan Fraser

Comedians:
Phil Hartman
Dana Carvey
Dan Aykroyd
Norm MacDonald
Martin Short
Howie Mandel
Mike Myers
Colin Mochrie
Leslie Nielsen
Dave Foley
Caroline Rhea

I'll probably add to this list as I realize how many more things/people are from Canada.