This is one that is not: http://my42cents.blogspot.com/.
No, its not the weird political 42 cents blog, though the author does address this.
The premise is simple. Taken from the website:
"The Correspondent writes a real letter and posts it each weekday. Bookmark the page and subscribe to the RSS feed to receive daily content. Please share the page with friends and family, so that they, too, may come to expect correspondence. If you have any comments or suggestions, both are welcome via the comment links below each letter."
My personal favorites, the letter to the first grade, Val Kilmer, and the Ice Mountain Water one (mainly good because, sometimes, the companies will reply back).
Lessons learned from this blog: write letters to companies, they usually give away free stuff. Also, a lot more people than I had imagined enjoy a personal letter from someone completely anonymous.
Fun stuff, check it out.