Bowling kata in 11 lines of clojure

bowling.clj

(defn- sum [s] (reduce + s))
(defn score
  ([gs] (let [s (clojure.string/replace gs #"\d/" #(str (nth % 0) (char (- 106 (int (nth % 0)))))),
              g (map #(case % \X 10 \- 0 (- (int %) 48)) s)]
          (score g 1)))
  ([game frame]   
     (cond
       (= frame 10)                (sum game)
       (= (first game) 10)         (+ (sum (take 3 game)) (score (drop 1 game) (inc frame))),
       (= (sum (take 2 game)) 10)  (+ (sum (take 3 game)) (score (drop 2 game) (inc frame))),
       :else                       (+ (sum (take 2 game)) (score (drop 2 game) (inc frame))))))

Line 3 deals with the spares
Line 4 deals with strikes and misses
Together, those lines produce a list of all the numbers of pins knocked down during the game, which is then processed by the 2-arity version of the function.