Scrambled Words
I think this only works with simple sentences containing short and familiar words. To test this, I wrote a little bookmarklet: scramble! If you bookmark this link (by using the context menu) and open it on any webpage, it will scramble the words on it. (If you click it, it will scramble the words on this page.) It should work in all browsers that support the W3C DOM, but I've only tested it in Mozilla.
[Update 2003-09-23]: I've updated the bookmarklet so that it doesn't count punctuation marks as parts of words any more.
[Another update 2003-09-23]: Sorry, there was a typo in the previous code.