mrtab : An iteration threshold table generator for the Miller-Rabin random probable prime search.
AVR-OSX-and-Olimex-ISP-MK2 : A guide to building an up-to-date AVR GNU toolchain, AVRDUDE patching, and Olimex AVR-ISP-MK2 firmware, for OS X (and UN*X / BSD).
I seem to refer people to the Lockless tutorial for (x86-64) GCC inline assembly quite often; there's a lot of hard-won experience to be found there.
The Autotools Mythbuster is an excellent guided approach to the autotools, with examples that build on previous chapters. The autotools manuals themselves provide no structured tutorials, and are only useful as reference works.