Just off the top of my head, people who are in this movie:
Greg Kinear (sp?)
Dennis Quaid
Kate Winslet
Hugh Jackman
Hale Berry
Richard Gere
Anna Faris
Elizabeth Banks
Kate Bosworth
Edward Norton
Johnny Knoxville
Patrick Warburton
Seth McFarlane
Naomi Watts
Chris Pratt
Kieren Kaulkin
Emma Stone
Jack McBreyer
Uma Therman
Kristen Bell
Gerard Butler
Sean William Scott
And they all agreed to be in a movie that was voted "worst movie of the year". That has to pique your interest.
EDIT: I Googled it and I got one wrong. Edward Norton is not in it. I thought he was one of the leprechauns for some reason...turns out that Gerard Butler was both of the leprechauns. Doesn't just the mention of "leprechauns" make this a must see flick?