I actually did this on two separate occasions. The first, which cannot be documented, was for school. For both my AP US History class and my AP English class, I had to read a college-level book and then write an informal review/report of the book. My APUS had one further requirement, being that it had to document some nature of American history. I read Michael B. Oren's Faith, Power, and Fantasy, a 600+ page volume about American involvement in the Middle East. All I did was write one essay and hand it in twice. Many people advised me not to, saying it verged on plagiarism. Of course, plagiarism is not really plagiarism if I used my own writing.

The second instance is documentable. I had a Blogger blog at hacbarton.blogspot.com. I wrote a really vague, 3-in-the-morning article. I then ditched that blog and started a Shoutpost blog at hacbarton.shoutpost.com. I copy/pasted said article onto the new blog to get myself started. The two can be found here with the 2 month difference noted in the posting date.
First: http://hacbarton.blogspot.com/2007/02/woody-allen-johnny-ramone-and-pat.html
Second: http://hacbarton.shoutpost.com/4762/that-way-madness-lies