Bluehat SEO has a great idea up on how to make $100 per day. He proposes creating some free screensavers and packaging them with the software from ZangoCash. Zango pays $0.45 per user download, so this could add up pretty quickly. The post very clearly lays out how you could get this up and running, and how to promote the site.

I probably will not be jumping on this anytime soon. Zango has a relatively shady past, including an large fine from the FTC. The idea is good for stimulating further thoughts. In the comments of the original post, people bring up some other good ideas such as putting URLs for sites with PPC ads on the screensaver.