These are bits and pieces I coded for my own personal use, mostly, and I have them here because you may find them useful too. If you have any ideas for improving these tools, or if you want to hack on the code, let me know.

Exefen »
Exefen is tool for easily adding XFN values to hand-rolled links. If you're using a system like WordPress to manage your links, adding rel values is a matter of a few clicks, and this tool brings that ease of use to any page on the world wide web. It parses a given page, returns all the external links, and lets you choose XFN values for each. When you submit it then returns the original markup enhanced with XFN for the links you specified.
Texturize »
Texturize is the most typographically advanced text-parsing code available.
Random Number Generator »
This is a tool I use at HPUG meetings to pick door prize winners. It picks a random number in a range you specify. I choose to use the Mersenne Twister functions.
Word Counter »
Word Counter is a simple tool to count the number of words in text you paste into it. It's slightly more intelligent than standard word-counters because it intelligently uses a dictionary of hyphenated words, word-break punctuation, and some logic that makes it a more accurate word counter than even many desktop programs like Word.