I have a few mainstream sites. Travel does extremely well and is pretty damn easy. Just make some specific sites basically copying information about destinations from various general tourism sites and sign up for referral commissions at
http://www.orbitz.com or
http://www.expedia.com or
http://www.site59.com & there's others too.
There's credit cards which are always pretty easy to make commissions from. Just do random searches for Credit on google and you will figure it out.
And if you don't wanna do that there's always the porn webmasters mainstream cousin... Viagra! You will be surprised how many family members ask you for a deal! You can always sell the other drugs for hair loss and fat burning too.
Gamma Cash has a great drugs program. Check it out.