Don't. It's not worth starting and it won't work. Denver is a boring city and you don't have enough of a viewing base to start anything. That's why everywhere else except Chicago, LA, and New York will fail. Miserably.
I obviously have some sort of viewing base, I did get an anonymous comment from you. :o)
Failure is always possible. Luckily, it's hard to fail miserably when there is little to no investment. Blogger is free. (See blogger.com for more information about this.)
Denver's not boring... you're just uninformed; but I agree it's definately not Chicago or New York, partially due to being more spread out and having lousy public transportation.
When I was in Chicago I took the El everywhere, and you hear some crazy stuff there - nothing like it in Denver.
Now you are wrong already because there already are several other successful websites for things overheard other places already. Plus, just keeping you informed... people actually speak and are overheard in nearly every place on earth, so the concept is still viable, regardless of anonymous commenters who just don't like Denver.