The Fedora Project is the free community release from enterprise Linux giant Red Hat. It's a testing ground really for a lot of new ideas which usually end up in the company's commercial Red Hat Enterprise products. I've used Fedora in the past on and off but for some reason it's never quite stuck with me. I've often found it buggy and a little too unstable due to it's experimental nature.
Distro base: Red Hat
Packaging: .rpm (Managed by Yum)
Linux Kernel: 2.6.25-14.fc9.i686
Default Desktop: Gnome 2.22.1