Rui Carmorlogger is a flatfile-based weblog engine that I threw together once to get my weblog up and running and sustain it with minimal effort. It is based on PHP, and I'm still using it for stuff like my photo log.
It has recently been pointed out to me that it is extremely similar to Bl0xsom in both approach and implementation, even though Bl0xsom is written in Perl - which just goes to show that I should have made my source code available from the outset. :)
Version 2.0 is in the works, but is unlikely to surface anytime soon. The code has morphed into a modular set that I keep adding to and re-using and re-tuning every time I need a new component, and as such has yet to settle enough for me to release it.