Can anyone suggest a small, simple and free bugtracker?

Question

I'm looking for a small and simple (emphasis on simple) bugtracker for a small project. It should run on Apache/PHP, though I'll consider other alternatives too (no Windows though). Oh, and I don't have any money to spend on it, so it should be free. :P

Any recommendations?

Added: Please, no hosted solutions. I want to host it myself.

Answer 1

Trac. It is free, simple, and runs on Apache. See the demosite to try it out yourself.