Shrek's M&M's

What's your guess?  How many Ogre-sized M&M's Milk Chocolate Candies will fill the Grand Canyon?

That's the current M&M's promotion to promote their largeer M&M's.  Pretty interesting for the following reasons:

• There is now enough information publicly available on the Internet to very accurately answer this question.
• Chances are that someone will come up with the correct answer and post it somewhere on the web (maybe even in a blog).
• This could very easily be a puzzle question for a Microsoft interview -- too bad they won't be able to use after the answer is announced (or maybe they should just to figure out what the interviewee's process was for determining the exactly correct answer on the Internet).