RIM employs a pretty absurd number of software engineering interns. If you've done software internships in Canada, odds are you've worked for RIM at some point.
I've also heard horror stories stemming from this - some teams have such a high reliance on interns (cheap labour, hurrah!) that code quality is truly abysmal.
Waterloo is a hub of software engineering education in one of the most populous areas of Canada. A LOT of Canadian computer geeks went to school there. By extension, lots of them have interned at RIM, as it is so close: http://www.rim.com/company/maps/index.shtml
