I just have to second this. I have a checkout of the OpenBSD source tree on all my machines. While tinkering with stuff, I often end up browsing the code unde

I just have to second this. I have a checkout of the OpenBSD source tree on all my machines. While tinkering with stuff, I often end up browsing the code under libc/, with great curiosity. Though there are many not-quite-so-pretty bits inherited from the dark ages, I can't say I've ever really felt confused. On the contrary, there's plenty of nice, inspiring code just waiting to be read. Oh, and there's superb documentation to go with it.