diff --git a/purescript.cabal b/purescript.cabal
--- a/purescript.cabal
+++ b/purescript.cabal
@@ -1,5 +1,5 @@
 name: purescript
-version: 0.2.11.1
+version: 0.2.13
 cabal-version: >=1.8
 build-type: Simple
 license: MIT
diff --git a/src/Language/PureScript.hs b/src/Language/PureScript.hs
--- a/src/Language/PureScript.hs
+++ b/src/Language/PureScript.hs
@@ -27,12 +27,19 @@
 import Language.PureScript.Options as P
 
 import Data.List (intercalate)
-import Control.Monad (forM_)
+import Control.Monad (when, forM_)
+import qualified Data.Map as M
 
 compile :: Options -> [Module] -> Either String (String, String, Environment)
 compile opts ms = do
   desugared <- desugar ms
   (_, env) <- runCheck $ forM_ desugared $ \(Module moduleName decls) -> typeCheckAll (ModuleName moduleName) decls
-  let js = prettyPrintJS . concatMap (flip (moduleToJs opts) env) $ desugared
+  let js = concatMap (flip (moduleToJs opts) env) $ desugared
   let exts = intercalate "\n" . map (flip moduleToPs env) $ desugared
-  return (js, exts, env)
+  js' <- case () of
+              _ | optionsRunMain opts -> do
+                    when ((ModuleName (ProperName "Main"), Ident "main") `M.notMember` (names env)) $
+                      Left "Main.main is undefined"
+                    return $ js ++ [JSApp (JSAccessor "main" (JSVar (Ident "Main"))) []]
+                | otherwise -> return js
+  return (prettyPrintJS js', exts, env)
diff --git a/src/Language/PureScript/CodeGen/Optimize.hs b/src/Language/PureScript/CodeGen/Optimize.hs
--- a/src/Language/PureScript/CodeGen/Optimize.hs
+++ b/src/Language/PureScript/CodeGen/Optimize.hs
@@ -28,6 +28,7 @@
 optimize opts =
   collapseNestedBlocks
   . tco opts
+  . magicDo opts
   . removeUnusedVariables
   . unThunk
   . etaConvert
@@ -133,7 +134,7 @@
   copyVar (Ident arg) = Ident $ "__copy_" ++ arg
   copyVar _ = error "Invalid name in copyVar"
   convert :: JS -> JS
-  convert js@(JSVariableIntroduction name (Just fn@(JSFunction Nothing _ _))) =
+  convert js@(JSVariableIntroduction name (Just fn@(JSFunction _ _ _))) =
     let
       (argss, body', replace) = collectAllFunctionArgs [] id fn
     in case () of
@@ -145,12 +146,14 @@
         | otherwise -> js
   convert js = js
   collectAllFunctionArgs :: [[Ident]] -> (JS -> JS) -> JS -> ([[Ident]], JS, JS -> JS)
-  collectAllFunctionArgs allArgs f (JSFunction Nothing args (JSBlock (body@(JSReturn _):_))) =
-    collectAllFunctionArgs (args : allArgs) (\b -> f (JSFunction Nothing (map copyVar args) (JSBlock [b]))) body
-  collectAllFunctionArgs allArgs f (JSReturn (JSFunction Nothing args (JSBlock [body]))) =
-    collectAllFunctionArgs (args : allArgs) (\b -> f (JSReturn (JSFunction Nothing (map copyVar args) (JSBlock [b])))) body
-  collectAllFunctionArgs allArgs f (JSReturn (JSFunction Nothing args body@(JSBlock _))) =
-    (args : allArgs, body, \b -> f (JSReturn (JSFunction Nothing (map copyVar args) b)))
+  collectAllFunctionArgs allArgs f (JSFunction ident args (JSBlock (body@(JSReturn _):_))) =
+    collectAllFunctionArgs (args : allArgs) (\b -> f (JSFunction ident (map copyVar args) (JSBlock [b]))) body
+  collectAllFunctionArgs allArgs f (JSFunction ident args body@(JSBlock _)) =
+    (args : allArgs, body, \b -> f (JSFunction ident (map copyVar args) b))
+  collectAllFunctionArgs allArgs f (JSReturn (JSFunction ident args (JSBlock [body]))) =
+    collectAllFunctionArgs (args : allArgs) (\b -> f (JSReturn (JSFunction ident (map copyVar args) (JSBlock [b])))) body
+  collectAllFunctionArgs allArgs f (JSReturn (JSFunction ident args body@(JSBlock _))) =
+    (args : allArgs, body, \b -> f (JSReturn (JSFunction ident (map copyVar args) b)))
   collectAllFunctionArgs allArgs f body = (allArgs, body, f)
   isTailCall :: Ident -> JS -> Bool
   isTailCall ident js =
@@ -194,6 +197,29 @@
   isSelfCall ident (JSApp (JSVar ident') _) | ident == ident' = True
   isSelfCall ident (JSApp fn _) = isSelfCall ident fn
   isSelfCall _ _ = False
+
+magicDo :: Options -> JS -> JS
+magicDo opts | optionsMagicDo opts = magicDo'
+             | otherwise = id
+
+magicDo' :: JS -> JS
+magicDo' = everywhere (mkT undo) . everywhere' (mkT convert)
+  where
+  fnName = Ident "__do"
+  convert :: JS -> JS
+  convert (JSApp (JSApp ret [val]) []) | isReturn ret = val
+  convert (JSApp (JSApp bind [m]) [JSFunction Nothing [Ident "_"] (JSBlock [JSReturn ret])]) | isBind bind =
+    JSFunction (Just fnName) [] $ JSBlock [ JSApp m [], JSReturn (JSApp ret []) ]
+  convert (JSApp (JSApp bind [m]) [JSFunction Nothing [arg] (JSBlock [JSReturn ret])]) | isBind bind =
+    JSFunction (Just fnName) [] $ JSBlock [ JSVariableIntroduction arg (Just (JSApp m [])), JSReturn (JSApp ret []) ]
+  convert other = other
+  isBind (JSAccessor "bind" (JSAccessor "eff" (JSVar (Ident "Eff")))) = True
+  isBind _ = False
+  isReturn (JSAccessor "ret" (JSAccessor "eff" (JSVar (Ident "Eff")))) = True
+  isReturn _ = False
+  undo :: JS -> JS
+  undo (JSReturn (JSApp (JSFunction (Just ident) [] body) [])) | ident == fnName = body
+  undo other = other
 
 collapseNestedBlocks :: JS -> JS
 collapseNestedBlocks = everywhere (mkT collapse)
diff --git a/src/Language/PureScript/Options.hs b/src/Language/PureScript/Options.hs
--- a/src/Language/PureScript/Options.hs
+++ b/src/Language/PureScript/Options.hs
@@ -17,7 +17,9 @@
 data Options = Options
   { optionsTco :: Bool
   , optionsPerformRuntimeTypeChecks :: Bool
+  , optionsMagicDo :: Bool
+  , optionsRunMain :: Bool
   } deriving Show
 
 defaultOptions :: Options
-defaultOptions = Options False False
+defaultOptions = Options False False False False
diff --git a/src/Main.hs b/src/Main.hs
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -82,8 +82,16 @@
 noPrelude = value $ flag $ (optInfo [ "no-prelude" ])
      { optDoc = "Omit the Prelude" }
 
+magicDo :: Term Bool
+magicDo = value $ flag $ (optInfo [ "magic-do" ])
+     { optDoc = "Overload the do keyword to generate efficient code specifically for the Eff monad." }
+
+runMain :: Term Bool
+runMain = value $ flag $ (optInfo [ "run-main" ])
+     { optDoc = "Generate code to run the main method in the Main module." }
+
 options :: Term P.Options
-options = P.Options <$> tco <*> performRuntimeTypeChecks
+options = P.Options <$> tco <*> performRuntimeTypeChecks <*> magicDo <*> runMain
 
 stdInOrInputFiles :: FilePath -> Term (Maybe [FilePath])
 stdInOrInputFiles prelude = combine <$> useStdIn <*> (not <$> noPrelude) <*> inputFiles