diff --git a/src/Graphics/Vty/Input/Events.hs b/src/Graphics/Vty/Input/Events.hs
index 6ae1cb0..4c960fd 100644
--- a/src/Graphics/Vty/Input/Events.hs
+++ b/src/Graphics/Vty/Input/Events.hs
@@ -1,6 +1,7 @@
 {-# Language DeriveGeneric #-}
 module Graphics.Vty.Input.Events where
 
+import Control.DeepSeq
 import Data.ByteString
 import GHC.Generics
 
@@ -21,16 +22,22 @@ data Key = KEsc  | KChar Char | KBS | KEnter
          | KHome | KPageUp | KDel | KEnd | KPageDown | KBegin | KMenu
     deriving (Eq,Show,Read,Ord,Generic)
 
+instance NFData Key
+
 -- | Modifier keys. Key codes are interpreted such that users are more
 -- likely to have Meta than Alt; for instance on the PC Linux console,
 -- 'MMeta' will generally correspond to the physical Alt key.
 data Modifier = MShift | MCtrl | MMeta | MAlt
     deriving (Eq,Show,Read,Ord,Generic)
 
+instance NFData Modifier
+
 -- | Mouse buttons.
 data Button = BLeft | BMiddle | BRight | BScrollUp | BScrollDown
     deriving (Eq,Show,Read,Ord,Generic)
 
+instance NFData Button
+
 -- | Events.
 data Event
     = EvKey Key [Modifier]
@@ -62,4 +69,6 @@ data Event
     -- ^ The terminal running the application gained input focus.
     deriving (Eq,Show,Read,Ord,Generic)
 
+instance NFData Event
+
 type ClassifyMap = [(String,Event)]