I've attempted to monetize a couple of websites, with various results (mostly disappointing). Otherwise, I do sports betting online, which can be a sure way to make money on a certain site I use (it just takes a while, but you can still get paid without ever putting a penny into the site).

Also, for anyone serious about starting a real online business, I'd suggest picking up or downloading the 4 Hour Workweek. Though I don't treat it like a bible at all, it's got some really helpful strategies both for work and for your personal life.