Recently, I found a great program : Filter Forge - Photoshop Plugin to Create Your Own Filters
It's basically an external filter creation tool that lets you make procedural textures as well as photo filters. There are some pretty amazing effects in the default set.
What's really neat in my opinion, though, is how they're marketing the program. It's in Beta, so it's not for sale, but if you (a) help them test the beta or (b) create filters that other people download and use, then they'll give you a copy for free when it's released.
You can submit your own filters to the Filter Library, and if they get popular with the Filter Forge users, you can earn rewards including a free copy of Filter Forge
What a great way to build a community as well as get the bugs worked out of the system. I've got my beta key and plan on doing some testing myself since this is they type of application I like the most. I've submitted two filters so far myself (Moistened Elephan Skin and Beer. 'Cuz that's what they look like) but they take some time to get approved.
A nice program with a neat twist on getting people interested. Hope I can do enough to get a free copy as well.