Gosh, took me more than five years to discover that the handy Notepad was designed to be a journal. And I quote from a mailing list I subscribe to (Thanks, Jon Lewis):
Open a blank Notepad file.
Write .LOG (in uppercase) in the first line of the file, followed by Enter.
Save the file and close it.
Double-click the file to open it and notice that Notepad appends the current date and time to the end of the file and places the cursor on the line after.
Type your notes and then save and close the file.
Each time you open the file, Notepad repeats the process, appending the time and date to the end of the file and placing the cursor below it.
Here's a site that gave it as a Tip of the Day in... uhm... April 2001: WUGNET.com
And here's the word from Microsoft in 2004:
How to Use Notepad to Create a Log File.
(Of course, it also applies to XP.)