MonadRandom package is a random number generation monad. It is now available in Fedora. Install it using:

$ sudo yum install ghc-MonadRandom-devel

The example of simulating a die is shown below:

import Control.Monad.Random

die :: (RandomGen g) => Rand g Int
die = getRandomR (1,6)

dice :: (RandomGen g) => Int -> Rand g [Int]
dice n = sequence (replicate n die)

main = do
  values <- evalRandIO (dice 1)
  putStrLn (show values)

Compile it using:

$ ghc --make die.hs 
[1 of 1] Compiling Main             ( die.hs, die.o )
Linking die ...

You can run it using:

$ ./die 
[3]
$ ./die 
[5]
$ ./die 
[1]
$ ./die 
[1]
$ ./die 
[6]

The fromList function produces a random value from a weighted list:

Prelude> :m + Control.Monad.Random
Prelude Control.Monad.Random> fromList [(1,2), (3,4), (5,6)]
5
Prelude Control.Monad.Random> fromList [(1,2), (3,4), (5,6)]
1
Prelude Control.Monad.Random> fromList [(1,2), (3,4), (5,6)]
5
Prelude Control.Monad.Random> fromList [(1,2), (3,4), (5,6)]
3
Prelude Control.Monad.Random> fromList [(1,2), (3,4), (5,6)]
1