As WordPress grows, it becomes possible to make more and more sites using the technology. Pages and the permalink structure give it CMS power, custom taxonomies and post types expand this further to differentiate chronological posts, pages and arbitrary objects, and plugins fill the gaps.
So, you can use WordPress to power your blog, photo gallery, and website. What are some of the more creative uses you've seen that exploit powerful WordPress features? What are some sites that made you say, "That's WordPress?"