Tiddlywiki is both good and bad.
If you haven’t heard of it, Tiddlywiki is a single file, off-line, single user “wiki” that you can use to store notes and information in an easy-to-retrieve format. I found it and decided I loved it…for about 6 hours. Now I’m looking at the source code and trying to understand it so I can rip out all the stuff I don’t like and replace it. Tiddlywiki doesn’t allow any sort of XHTML and requires all code to be done in textile.