diff --git a/happstack-server.cabal b/happstack-server.cabal
--- a/happstack-server.cabal
+++ b/happstack-server.cabal
@@ -1,5 +1,5 @@
 Name:                happstack-server
-Version:             6.6.3
+Version:             6.6.4
 Synopsis:            Web related tools and services.
 Description:         Happstack Server provides an HTTP server and a rich set of functions for routing requests, handling query parameters, generating responses, working with cookies, serving files, and more. For in-depth documentation see the Happstack Crash Course <http://happstack.com/docs/crashcourse/index.html>
 License:             BSD3
diff --git a/src/Happstack/Server/Internal/TimeoutManager.hs b/src/Happstack/Server/Internal/TimeoutManager.hs
--- a/src/Happstack/Server/Internal/TimeoutManager.hs
+++ b/src/Happstack/Server/Internal/TimeoutManager.hs
@@ -3,6 +3,7 @@
     , Handle
     , initialize
     , register
+    , registerKillThread
     , tickle
     , pause
     , resume
@@ -10,14 +11,15 @@
     ) where
 
 import qualified Data.IORef as I
-import Control.Concurrent (forkIO, threadDelay)
+import Control.Concurrent (forkIO, threadDelay, myThreadId, killThread)
 import Control.Monad (forever)
 import qualified Control.Exception as E
 
 -- FIXME implement stopManager
 
+-- | A timeout manager
 newtype Manager = Manager (I.IORef [Handle])
-data Handle = Handle (IO ()) (I.IORef State)
+data Handle = Handle (I.IORef (IO ())) (I.IORef State)
 data State = Active | Inactive | Paused | Canceled
 
 initialize :: Int -> IO Manager
@@ -35,7 +37,8 @@
         state <- I.atomicModifyIORef iactive (\x -> (go' x, x))
         case state of
             Inactive -> do
-                onTimeout `E.catch` ignoreAll
+                action <- I.readIORef onTimeout
+                action `E.catch` ignoreAll
                 go rest front
             Canceled -> go rest front
             _ -> go rest (front . (:) m)
@@ -48,12 +51,20 @@
 register :: Manager -> IO () -> IO Handle
 register (Manager ref) onTimeout = do
     iactive <- I.newIORef Active
-    let h = Handle onTimeout iactive
+    action  <- I.newIORef onTimeout
+    let h = Handle action iactive
     I.atomicModifyIORef ref (\x -> (h : x, ()))
     return h
 
+registerKillThread :: Manager -> IO Handle
+registerKillThread m = do
+    tid <- myThreadId
+    register m $ killThread tid
+
 tickle, pause, resume, cancel :: Handle -> IO ()
-tickle (Handle _ iactive) = I.writeIORef iactive Active
-pause (Handle _ iactive) = I.writeIORef iactive Paused
+tickle (Handle _ iactive) = I.writeIORef iactive $! Active
+pause (Handle _ iactive) = I.writeIORef iactive $! Paused
 resume = tickle
-cancel (Handle _ iactive) = I.writeIORef iactive Canceled
+cancel (Handle action iactive) = 
+    do I.writeIORef iactive $! Canceled
+       I.writeIORef action $! (return ())