diff --git a/Yesod/Routes/Parse.hs b/Yesod/Routes/Parse.hs
--- a/Yesod/Routes/Parse.hs
+++ b/Yesod/Routes/Parse.hs
@@ -184,6 +184,7 @@
 
 pieceFromString :: String -> Either String (CheckOverlap, Piece String)
 pieceFromString ('#':'!':x) = Right $ (False, Dynamic x)
+pieceFromString ('!':'#':x) = Right $ (False, Dynamic x) -- https://github.com/yesodweb/yesod/issues/652
 pieceFromString ('#':x) = Right $ (True, Dynamic x)
 pieceFromString ('*':x) = Left x
 pieceFromString ('+':x) = Left x
diff --git a/test/Hierarchy.hs b/test/Hierarchy.hs
--- a/test/Hierarchy.hs
+++ b/test/Hierarchy.hs
@@ -77,6 +77,8 @@
     let resources = [parseRoutes|
 / HomeR GET
 
+/!#Int BackwardsR GET
+
 /admin/#Int AdminR:
     /            AdminRootR GET
     /login       LoginR     GET POST
@@ -140,6 +142,9 @@
 
 getHomeR :: Handler site String
 getHomeR = "home"
+
+getBackwardsR :: Int -> Handler site Text
+getBackwardsR _ = pack "backwards"
 
 getAdminRootR :: Int -> Handler site Text
 getAdminRootR i = pack $ "admin root: " ++ show i
diff --git a/yesod-routes.cabal b/yesod-routes.cabal
--- a/yesod-routes.cabal
+++ b/yesod-routes.cabal
@@ -1,5 +1,5 @@
 name:            yesod-routes
-version:         1.2.0.5
+version:         1.2.0.6
 license:         MIT
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>