I have google adsense. Now that I have more time to myself because of my new shiftwork job, I will probably look at modernizing my sites, adding more stuff, so I can draw more visitors. I only get 50-100/mo through it so it's not like it covers much bills. It does help cover hosting and that's about it. I also have a donation system for my game server, when people donate they get game points they can use to get stuff. But that too, barely covers the hosting cost.
I've been wanting to get into web hosting but it's a conflict of interest with the company I work for. In fact almost any web service is, which kinda sucks. There's lot of things I'd like to do but can't.
I've thought of making a game like Evony. That's a gold mine right there.
At some point when I have extra money I'd like to buy houses and flip them too. Tons of cash to be made with this.