derived from http://ideone.com/ajhkl3

gistfile1.txt

import Control.Parallel.Strategies

fib :: Integer -> Integer
fib 0 = 0
fib 1 = 1
fib n = fib (n-1) + fib (n-2)

main = print . snd . runEval $ do
         x <- rpar $ (undefined :: Integer) -- (fib 100)
         y <- rpar (fib 100)
         return (x,y)

あわせてご覧ください：　元ネタ　http://ideone.com/ajhkl3