Wordcount

This has to be one of the most mesmorising, hypnotic, addictive things I've played with for a while: Wordcount (http://www.wordcount.org/). From the description:

WordCount™ is an artistic experiment in the way we use language. It presents the 86,800 most frequently used English words, ranked in order of commonality. Each word is scaled to reflect its frequency relative to the words that precede and follow it, giving a visual barometer of relevance. The larger the word, the more we use it. The smaller the word, the more uncommon it is.

It's hard to describe really. Just have a play!