DouKaku?

import Data.Time
import Data.Time.Calendar.OrdinalDate

isFriday d =
  case sundayStartWeek d of
    (_, 5)    -> True
    otherwise -> False

main = do
  today <- getZonedTime >>= \ zt -> (return.localDay.zonedTimeToLocalTime) zt
  let fridays = filter isFriday $ filter (today <=) [fromGregorian y m 13 | y <- [2008..2013], m <-[1..12]]
  mapM_ (putStrLn.show) fridays
  putStrLn $ (show $ length fridays) ++ " days"