Amy Hughes has built a Lego church of truly astonishing proportions. She estimates it contains 75,000 pieces! She also has other projects in more modest, but still quite large, scales. And I liked the faux-Biblical verses she provides from Slashdot:

And on the eighth day, God created plastic, and He saw that it was good, and He made little teeny-tiny blocks out of it to give geeks something very cool to play with.

And bare of foot, man did step upon teeny-tiny blocks of plastic, and he did blaspheme.