Lazier than lazy

If you can't put off what you have to do, ask someone else to do it for you.

(defn off
 "Computes a lazy-seq in another (dedicated) thread."
 [s]
  (let [ex (. java.util.concurrent.Executors newSingleThreadExecutor)]
    ((fn this [s]
       (if s 
         (let [future-rest (java.util.concurrent.FutureTask. #(rest s))]
           (.execute ex future-rest)
             (lazy-cons (first s) (this (.get future-rest))))
         (.shutdown ex))) s)))