Even more interesting, happs (http://happs.org) http://happs.org) combines a number of things: a prevayler-style in memory persistence layer, twisted-style even

Even more interesting, happs (http://happs.org) http://happs.org) combines a number of things: a prevayler-style in memory persistence layer, twisted-style event-driven programming, and SEDA-style non-blocking IO. It's built in haskell, which really is a beautiful language if you can wrap your head around it. Much like lisp in that sense.