Wordle
Wordle uses Java to generate an image from whatever text you input (h/t: Yet Another Comics Blog). It's basically a tag cloud, but cooler because it's more configurable (you can change the font and the colors, vary the number of words and the layout, etc.). Here's Bertrand Russell's "Why I Am Not a Christian" all Wordle-ified:
Kudos to developer Jonathan Feinberg for generating such a delightful typographic time-sink!