This website has so much content it’s amazing to me when I see the work of IA’s that know what they are doing like in this example. There’s also a very subtle and well done interaction experience going on in almost every nook & cranny of the page.
The search field alone in the header area, with that slide-down search configuration (the wrench icon) is very nice. The sub pages for the congress listings is also so very well done. And I love the donate page most of all, those graphs on the sidebar make me happy.