Kircher Society has a neat entry on Robert Shields of Dayton, Washington, who probably holds the world record of longest diary:
For twenty years, Robert Shields of Dayton, Washington, has kept a written record of absolutely everything that has happened to him, day and night. For no less than four hours each day, Shields holes himself up in the small office in his home, turns on his stereo, and types. His diary, at 35 million words, is believed to be the world’s longest.
Shields did this from 1972 until 1996, when he was disabled by a stroke. Shown above is a page from the diary, showing what he did every 5 minutes interval! http://www.kirchersociety.org/blog/?p=140