The backend is a typical LAMP stack with the Symfony2 framework backing the P. Varnish sits in front of all the Chef managed Linode boxes. The site will work without Javascript (up until the checkout), and the style degrades really nicely depending on your viewport (try it out by resizing your browser).
I'm open to all comments and critiques, so let me hear them. And if you are into graphic t-shirts, here is a code for a Hacker News 20% discount: 4803-7940-0816-5604!