My SIWOTI flared up, and while I had little hope that the Noachian creationist would give it any consideration, I wrote a simple evolution model demo thing. It's very simple, but can demonstrate simple natural selection.
To run it, you'll need Python 2.5 or 2.6.
The top of the source code contains a number of parameters that you can tweak.
Perhaps the simplest method of compression is run length encoding. When faced with the string "AAAAAAAAAAAAAAAAA", if asked to describe it to another person, most people's first instinct would be to count the number of As, and tell the other person "17 'A's", at which point the other person perversely writes down the string "SEVENTEEN AYES", showing up one of the problems with this approach: distinguishing talking about the data from the data itself.
What is compression?
A compression algorithm that maps a set of strings A to another set of strings B, with the goal of mapping strings in A that are believed to be more likely to occur to shorter strings in B. There are two important details here: "shorter", and "more common".
Because somebody asked for it, I modified my LJ post locker to (hopefully) delete the entries instead. Not having a journal I want erased, I haven't actually tested it myself.
A friend of mine wanted to lock all of the public entries of her LJ, but not having a paid account, she couldn't use the built-in tools. As a result, I wrote a tool that will friend lock all public entries in a Livejournal (or, with a small bit of work, any other journal supporting the LJ API), but not touch any private or existing friend-locked posts. There's no GUI for it, and it takes the username and password from the controlling terminal.
Requires Python.
After seeing Kevan's Zombie infection simulator, I decided to make my own. To balance the odds, I added a way for humans to fight back, arming themselves with randomly distributed chainsaws. Now the humans can sometimes, but not always, win.
A friend of mine wanted to view filtered set of posts by certain Friends, based on what tags they placed on the post. Rather than wait for Six Apart to implement something like that, I coded up a work-around, using each journal's RSS feed. It's not perfect---you can only see public posts---but it's better than nothing. http://pnakotic.com/friendfilter/
I couldn't find an IPS patcher for Linux so I wrote my own. No guarantees that it will work, but it has patched at least one ROM for me and it worked after.
The source code for LinIPS can be found at http://alfedenzia.com/linips.c
A simple script for posting predefined events to Livejournal (or, with a bit of fiddling with the source, any other journal that supports the LJ XML RPC API) at predefined times. You can download it at http://alfedenzia.com/ljcronpost.py
