This is the web of a Desertshrub Spider (aka Desert Bush Spider); the link is to a blog post from Bug Eric (thanks, Angie) with more info (and photos! Don't click, Honey-Matt!). What looks like debris in the middle of this photo is called a retreat; made of leaves, remains of prey, whatever is around. The retreat is what generally catches your eye (not literally) when you are out and about. Take a closer look!