I started reading Samuel Pepys diary earlier this year and I've read about half of it so far.  Pepys wrote a diary in 17th century England.  His diary is one of the leading historical accounts of the time and I've really enjoyed reading it so far.  I was just Googling for the next book I wanted to get and found his blog!  The site owners are publishing the diary in the form of a blog in "real time", just 343 years after he wrote it.

For more info on the complete set of books of the diary see the University Of California Press page for the Latham and Matthews editions