Go-OO: The best office suite you never knew you used
If you run Ubuntu, openSUSE, Debian, or Mandriva, among other distributions, then whenever you run OpenOffice.org you don't run the "official" version, but rather Go-OO, an office suite based on the OpenOffice.org source code. Go-OO includes enhancements and functions that haven't been accepted by Sun, and that may never be, because of licensing, business, or other reasons.
Sun, the major contributor to OpenOffice.org, applies its own set of rules on the project's development, licensing, and copyrights, and as a result, there are often clashes with the general open source community. (Read this interview with an OpenOffice.org developer for more inside info on the Go-OO/OpenOffice.org rift.) Novell is the main mover behind Go-OO, but Debian and Ubuntu developers are also cooperating by maintaining a large group of patches, and making sure they don't break newer OpenOffice.org releases. There used to be a certain lag between Go-OO releases and OpenOffice.org's, but now both variants come out quite close.