I setup Trac at work today (among other things). I spent maybe 20 minutes doing the setup on our Fedora Webserver, instructions can be found here, or if you have a different server OS search for your combination lots are documented.

After setup I spent 10 minutes quickly adding a skeleton for an in-house project starting next week. Trac provides a Wiki, so I instantly had pages describing project requirements, and the various components involved. Also included are issue tracking, subversion browsing, and milestones. Quite frankly, Trac looks awesome. Which is most likely why it is used in so many places.

I wish I had something like Trac setup when we started the last big project. Or even just for my time as a student: being able to document your entire semester and track issues you need to resolve would have been awesome.