Ubuntu, Kubuntu, Xubuntu, Fluxbuntu
One of the reasons why free software will ultimately triumph is that it is based on the eminently sensible idea of building on other people's work. That is, you do not need to re-invent something from scratch, but can take the achievements of others and improve upon them - and then make your own efforts available for further development.
This can happen at the level of sub-routines, chunks of code, libraries, applications and even distributions. Oen of the most dramatic examples of the latter is the proliferation of the Ubuntu family.
This was originally based on the GNOME desktop, so those who preferred KDE soon took the code and swapped in the latter to produce Kubuntu. Others, who prefer the Xfce desktop environment, have come up with Xubuntu. And now, for lovers of the svelte Flux Box desktop, there is Fluxbuntu. Screenshots are available to whet your appetite.