Ask Yahoo!:

Dear Yahoo!:
Why are so many movies filmed in Vancouver?
Megan
Los Angeles, California

Dear Megan:
A good number of movies and TV shows are indeed shot north of the border. And while it may seem odd for studios and networks to create their masterpieces so far from Hollywood, their reasoning is actually quite simple. Money.

Filmmakers can save a lot by working in Canada. This article from Slate.com explains that while Tinseltown has excellent soundstages and technicians for interior shots, filming outdoors in Los Angeles (or anywhere in the United States) gets very expensive very quickly. Up in Canada's smog-free air, things are a lot cheaper.

Canada has unionized labor, but it comes at a significant discount (up to 35% in the late 1990s). Additionally, the Canadian government subsidizes costs and offers a rebate on digital effects (if they're done in Canada and the filmmakers employ either a Canadian director, screenwriter, or highly paid star). Other discounts, rebates, and tax breaks apply.

Although your question specifically referenced Vancouver, the beautiful western city isn't the only Canadian destination to host Hollywood productions. Toronto frequently serves as a cheap alternative to filming in New York City, and "Calgary can often pass for the American West."

So, let's hear it for Canada, eh? Without their bargain prices, we'd all probably be paying $15 per movie ticket.