I've posted a link to my simple wiki engine on the web.py wiki and my programming projects page.
Originally I was using a tool I'd written that took up three or four files and about 400 lines of code. I got sick of browsing through all that to make simple changes so I wanted to see how tight I could get, while not skimping on my favorite features. The result is less than 75 lines of my own code and two simple templates, rather than 300+ lines and at least 4 templates. 80% of the features are still in and I've even managed to add some nice text preprocessing.
It's VERY easy to create and edit pages, and very easy to link and combine them in interesting ways. The include feature was a recent addition, taken from infogami's own page includes.
I've learned a ton about regular expressions and simplifying code so I figure it's been well worth it to create my own wiki. Web.py worries about the web, all I have to worry about is function.
Inspirations include infogami, the first web.py simple wiki, and TinyWiki, a one hundred line perl based wiki. My goal is not to stick to a certian size, and certianly not to re-write TinyWiki. I want to have a tool I can KNOW. Something I've made that I can actually use. For me, this is a much bigger programming step than just creating something that WORKS. It's useful, it has actual utility. Some efficiency friendly text-editing would be nice, but isn't really neccessary. I can track information, create documents, and "think out loud" without having to worry about files, archives and text-editors. Everything I need is in the browser.
In less than 80 lines I have something that is useful and I enjoy using, and that's more inspiring to me than all the programming puzzles in the world.

