If you haven't heard of The Million Dollar Homepage I would suggest checking it out. It's a very simple concept - this guy is selling blocks of pixels on his home page for $1 per pixel. He's got an image 1000x1000 pixels in size, which works out to one million dollars. There's a small catch in that you can only buy pixels in blocks of 10x10 for $100, but still...that's pretty cheap advertising! It looks like he's almost sold out. In fact, he's auctioning off the last 1,000 pixels on ebay. As of this writing the current bid on the auction is $152,300. An extremely simple idea. Very low initial investment. Huge returns. Brilliant.