http://genode.org/documentation/general-overview/index
It's a secure microkernelly capability-based OS where each process is basically a virtualised hypervisor; it can run a conventional OS as a user process, but it's also got a Unix-like native personality if you want it. I believe it's nearly self-hosting.
I wonder how long it will be before the turtle pokes its head out?
http://cyberneticzoo.com/cyberneticanimals/1969-the-logo-tur...
I was waxing lyrical at the Plan9 conference to Richard who I have known for a few years about how amazing the turtle and Logo is/was for classrooms because it could engage with a wider range of children than trying to teach them programming because it stimulated those maybe interested in programming, art, robotics, languages and maths with teamwork and communication skills and even just watching things happening. Imagine my pleasure when he said "I'm glad you appreciate it" and went on to tell me the story of developing it when I had no idea!
Edit: wow, he's everywhere.
Meanwhile Linux has always been a boring SysV Unix clone that only occasionally ripped some features (and in a questionable manner) like procfs, sysfs, epoll, signalfd so you don't have to do the self-pipe trick, inotify, cgroups and namespaces. Stuff that competing systems often did much better.
The BSDs have been quicker to do more novel things, but by far the only two modern Unices to get the memo are DragonFly BSD and Solaris/illumos.