If you're into this type of stuff check out Smash the stack[1] It has a bunch of memory type vulnerability wargames (specifically the IO level) for your choosing. They start off basic, like the one you presented in the blog, then more advanced topics like heap overflows, return 2 libc, SEH overwrites, GOT overwrites, ROP techniques etc.
like WestCoastJustin pointed out phrack has phenomenal articles but require you to have a fairly strong understanding of C and Operating system type things.