Lasersaur is an open source laser cutter project that is well documented and has community behind it. If you want to make your own CO2 laser cutting system for cutting trough wood, paper or leather (and some other materials) this is a project you want to study.
There are some problems, bugs and issues so you should look at the extensive video in the bottom of the post.
My lasersaur inspired 80w laser cutter. from Isaiah Bellais on Vimeo.
Lasersaur cuts Lasersaur from jody culkin on Vimeo.
Lasersaur (open source laser cutter) assembly timelapse. Feb 2013 from colaborativa on Vimeo.
When you need to cut stuff with a laser and you just have to do-it-yourself ...
Here is the detailed presentation about practical experiences of building and working with Lasersaur including problems of the system: