NetBSD other than being super portable (dozens of CPU architectures) has spawned some amazing projects that can't be mentioned enough.<p>* [pkgsrc](<a href="http://pkgsrc.org/" rel="nofollow">http://pkgsrc.org/</a>), a super portable and flexible ports system that is used per default on NetBSD, SmartOS, Minix, some Linux distributions, at DARPA, etc. Support for over 20 operating systems (as in <i>actually</i> different OS kernels)
* [Lua Scripting in the kernel [PDF]](<a href="https://www.netbsd.org/gallery/presentations/mbalmer/fosdem2012/kernel_mode_lua.pdf" rel="nofollow">https://www.netbsd.org/gallery/presentations/mbalmer/fosdem2...</a>)
* [A PGP implementation](<a href="http://www.netpgp.com/faq.html" rel="nofollow">http://www.netpgp.com/faq.html</a>)
* [A test framework for operating systems](<a href="https://wiki.netbsd.org/tutorials/atf/" rel="nofollow">https://wiki.netbsd.org/tutorials/atf/</a>)
* [Binary Interfaces for Linux, FreeBSD, SCO Unix, Tru64, Win32, Solaris, SVR4, Ultrix](<a href="https://www.netbsd.org/docs/compat.html" rel="nofollow">https://www.netbsd.org/docs/compat.html</a>)<p>Also they have all the stuff like FUSE, used to be pretty big in the Xen world (mostly for the high level portability), recently developed a [pretty nice SMP focused network filter](<a href="https://www.netbsd.org/~rmind/npf/" rel="nofollow">https://www.netbsd.org/~rmind/npf/</a> were the first to implement various drives (including implementing support for Apple hardware, before an OS from them officially supported it), their network stack I think still holds the the record for the fastest intercontinental file transfer ever done, etc. They also are pretty secure, which is mostly due to a strong quality focus.<p>But I think their devs are too busy achieving all those things, rather than hyping the OS, so that's why I have to. ;)<p>EDIT: Oh and despite all that research and so on, they always remained very pragmatic and non-political. That combination is really rare I think.