in my time on earth, i've learned that the ideas that tend to make people the most money are the ones that, if someone described them to you, would seem almost too simple to be believed.
here is a really good example. this guy is selling space on his web site in $100 blocks. you can own a little piece of his virtual wall with your logo or picture or whatever linked to your site.
while you're busy laughing yourself sick over the idea that people would pay $100 to have a tiny little logo displayed on a page alongside thousands of other tiny little logos, perhaps you'd like to count the number that are there and do the math as to how much this guy has actually brought in. (Or, if you want to make it simple, just check the stats on his site)... now how smart are you?