BM Project Ultra Light
After searching for a simple project manager I just decided a while ago to make one based solely on drupal core to avoid any upgrade issues.
The whole thing came out rather well, so now I'll alpha test it with my own projects to ready the beta version. The beta will be done when I've themed it a bit more (now it just uses a garland derivative).
Simplicity is a virtue, and I am always astounded at what can be done with drupal core if you only think a little out of the box.
At this point it has no automatic features, but it does have coloring for the background and the statuses which helps a lot.
I'll update on this at http://www.bobbymods.com/projects/bm-project-ultra-light