As noted on the site, this is "the professional badass's base HTML/CSS/JS template for a fast, robust and future-proof site" While I likely won't use this whole, there are some very interesting pieces to this worth using, especially in the style sheet and .htaccess files. I'll likely appropriate many of the concepts for my work.
This is an outstanding contribution to the Web development community by Paul Irish and Divya Manian as well as all of the people whose work they built upon.