The Pew Forum on Religion & Public Life
If you like statistics and the religious landscape of the United States, have I got a site for you to see. While the poll often confirmed well-understood cultural phenomena (65% of America’s Mormons are Republican or Republican-leaning), it also yielded some surprising results (2% of atheists’ prayers are answered daily[.pdf warning]). The site is pretty good; there are lots of ways to view and compare the data.
If you find anything interesting there, be sure to leave a comment here.