Paul Graham designs programming languages. As far as I can tell, he started to become a bit of an internet celebrity with a heavily referenced essay on filtering spam e-mail a few months back.
Now he presents The Hundred Year Language, considering how code might look that far into the future. He’s an excellent writer, so check it out even if you’re not a programmer.
And when you’re done with that one, check out his essay on the difference between design and research.