I've been all for the Olympics since day one, and for me it's two things. Firstly, it's seeing critical city infrastructure getting built, which could include a (sorely needed) new stadium and arena, an LRT connection to the airport and more downtown high-rise hotels. Olympics would be the right 'kick in the ass' that these types of developments need in order to proceed.
Secondly, I love sports, I want to see the world's best come and play in our backyard and I want to see many of our local businesses benefit from the associated tourism. I'd like to see Calgary established as a leader in sports, athletic and leisure industries (and its associated corporate industries) as a way to diversify our local economy.
That's just my opinion though, and I know most don't share it. And that's totally okay.