Compiz Fusion
I doubt many of you will have heard of Compiz or its one time rival Beryl. These are add-ons for Linux desktops which, though they have their advantages for making your computer more productive, are very much fancy eye-candy. Basically, whenever my friends ask why I use nix I show them some Compiz features, they then exclaim how cool they are and ask how to make their computer do that. They can't of course because they use archaic operating systems.
Anyway, I digress. Compiz is a window composting manager project (you'll see what I mean when you watch the film) which had some infighting, a common thing in open source communities where everyone has the right to say their piece. A group split to go form the Beryl project. Now, though Beryl was often the more exciting project, I preferred Compiz for its stability.
Since then the two groups have decided to re-merge, thus pooling their knowledge and avoiding doubling their work. I'll admit that I was skeptical about what the result would be, would Compiz stop being stable? Would Beryl become less exciting? The following video shows that Compiz Fusion (as the joint project is now known) has certainly become even more exciting than Beryl was alone. I'm now looking forward to installing it to see if its still as stable, even on my cheap integrated graphics card.