It struck me how well Carmack's ideas about running all actors in the game world in parallel map to Clojure's agents[1].

Clojure introduces a bunch of interesting ideas on how to handle parallel programming. "Perception and Action" by Stuart Halloway is a great talk to listen to if you're interested[2].

[1] http://clojure.org/agents [2] http://www.infoq.com/presentations/An-Introduction-to-Clojur...