diff --git a/bearriver.cabal b/bearriver.cabal
--- a/bearriver.cabal
+++ b/bearriver.cabal
@@ -1,5 +1,5 @@
 name:                bearriver
-version:             0.13.1.2
+version:             0.13.1.3
 homepage:            keera.co.uk
 license:             BSD3
 license-file:        LICENSE
@@ -36,7 +36,7 @@
   exposed-modules:     FRP.Yampa,
                        FRP.BearRiver
 
-  build-depends:       base >=4.6 && <5, transformers >=0.3, mtl, dunai >= 0.6.0 && < 0.8, MonadRandom, simple-affine-space
+  build-depends:       base >=4.6 && <5, transformers >=0.3, mtl, dunai >= 0.6.0 && < 0.9, MonadRandom, simple-affine-space
   hs-source-dirs:      src/
   default-language:    Haskell2010
 
diff --git a/src/FRP/BearRiver.hs b/src/FRP/BearRiver.hs
--- a/src/FRP/BearRiver.hs
+++ b/src/FRP/BearRiver.hs
@@ -53,6 +53,32 @@
 data Event a = Event a | NoEvent
  deriving (Eq, Show)
 
+-- | The type 'Event' is isomorphic to 'Maybe'. The 'Functor' instance of
+-- 'Event' is analogous to the 'Functo' instance of 'Maybe', where the given
+-- function is applied to the value inside the 'Event', if any.
+instance Functor Event where
+  fmap _ NoEvent   = NoEvent
+  fmap f (Event c) = Event (f c)
+
+-- | The type 'Event' is isomorphic to 'Maybe'. The 'Applicative' instance of
+-- 'Event' is analogous to the 'Applicative' instance of 'Maybe', where the
+-- lack of a value (i.e., 'NoEvent') causes '(<*>)' to produce no value
+-- ('NoEvent').
+instance Applicative Event where
+  pure = Event
+
+  Event f <*> Event x = Event (f x)
+  _       <*> _       = NoEvent
+
+-- | The type 'Event' is isomorphic to 'Maybe'. The 'Monad' instance of 'Event'
+-- is analogous to the 'Monad' instance of 'Maybe', where the lack of a value
+-- (i.e., 'NoEvent') causes bind to produce no value ('NoEvent').
+instance Monad Event where
+  return = pure
+
+  Event x >>= f = f x
+  NoEvent >>= _ = NoEvent
+
 -- ** Lifting
 arrPrim :: Monad m => (a -> b) -> SF m a b
 arrPrim = arr
@@ -176,16 +202,6 @@
 
 -- * Events
 
-instance Functor Event where
-  fmap f NoEvent   = NoEvent
-  fmap f (Event c) = Event (f c)
-
-instance Applicative Event where
-  pure = Event
-
-  Event f <*> Event x = Event (f x)
-  _       <*> _       = NoEvent
-
 -- | Apply an 'MSF' to every input. Freezes temporarily if the input is
 -- 'NoEvent', and continues as soon as an 'Event' is received.
 mapEventS :: Monad m => MSF m a b -> MSF m (Event a) (Event b)
@@ -448,14 +464,21 @@
 -- ** Parallel composition over collections
 
 parC :: Monad m => SF m a b -> SF m [a] [b]
-parC sf = parC' [sf]
+parC sf = parC0 sf
+  where
+    parC0 :: Monad m => SF m a b -> SF m [a] [b]
+    parC0 sf0 = MSF $ \as -> do
+      os <- T.mapM (\(a,sf) -> unMSF sf a) $ zip as (replicate (length as) sf0)
+      let bs  = fmap fst os
+          cts = fmap snd os
+      return (bs, parC' cts)
 
-parC' :: Monad m => [SF m a b] -> SF m [a] [b]
-parC' sfs = MSF $ \as -> do
-  os <- T.mapM (\(a,sf) -> unMSF sf a) $ zip as sfs
-  let bs  = fmap fst os
-      cts = fmap snd os
-  return (bs, parC' cts)
+    parC' :: Monad m => [SF m a b] -> SF m [a] [b]
+    parC' sfs = MSF $ \as -> do
+      os <- T.mapM (\(a,sf) -> unMSF sf a) $ zip as sfs
+      let bs  = fmap fst os
+          cts = fmap snd os
+      return (bs, parC' cts)
 
 -- * Discrete to continuous-time signal functions