I just finished the very fun short story collection jwgh sent me a while ago, Paul Di Filippo's Ribofunk. It ends with a pleasantly upbeat little tale of future tyranny and doom in what I've dubbed The Enormous Chinese Room (thanks to E.E. Cummings and John Searle), where a colony creature of tiny molecular replicators has taken over the planet by replacing everyone and everything with exact copies of themselves. There are so many different levels of understanding that this story approaches in such a simple way, it reminded me a lot of Brian W. Aldiss (and reminded me that I need to remember to read a lot more of him).