What kind of site to start for moderate income?

What kind of site should I start for moderate income? I am going to have some cash to drop ($200+ steady flow of more $) and I would like to start a site that will bring some income after a month or two of hard work.

Should I spend the money on a new site? If so what kind?

I have 2 current sites.
1) www.flash-matic.com - Flash game arcade, recently reconfigured and lost many members/games.

I have seen people write they dropped $100 onto adwords and made it back that night on YPN and are making $500-1000 monthly profit. (Still waiting for my new YPN approval, think I had one but lost it in email problems)

2) www.worldslargestforum.com - Misc forum thats still in dev but going nicely.
Not made for making money but maybe $100 in adwords might boost its growth after all the customizations are done.

Thanks,
Flash-matic