diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index fe68d4617cb..9cbfbe1b3f8 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -1811,6 +1811,23 @@ pythonPackages = modules // import ./python-packages-generated.nix {
     };
   };
 
+  pew = buildPythonPackage rec {
+    name = "pew-0.1.9";
+
+    src = fetchurl {
+      url = "https://pypi.python.org/packages/source/p/pew/${name}.tar.gz";
+      md5 = "90a82400074b50a9e73c3045ed9ac217";
+    };
+
+    propagatedBuildInputs = [ virtualenv virtualenv-clone ];
+
+    meta = with stdenv.lib; {
+      description = "Tools to manage multiple virtualenvs written in pure python, a virtualenvwrapper rewrite";
+      license = licenses.mit;
+      platforms = platforms.all;
+    };
+  };
+
 
   pudb = buildPythonPackage rec {
     name = "pudb-2013.3.6";
@@ -4875,11 +4892,11 @@ pythonPackages = modules // import ./python-packages-generated.nix {
 
 
   py = buildPythonPackage rec {
-    name = "py-1.4.19";
+    name = "py-1.4.20";
 
     src = fetchurl {
       url = "https://pypi.python.org/packages/source/p/py/${name}.tar.gz";
-      md5 = "d2e24b4363d834bf9192247f143435bc";
+      md5 = "5f1708be5482f3ff6711dfd6cafd45e0";
     };
   };
 
@@ -7055,16 +7072,18 @@ pythonPackages = modules // import ./python-packages-generated.nix {
 
 
   # TODO
-  # py.error.EACCES: [Permission denied]: mkdir('/homeless-shelter',)
-  # builder for `/nix/store/0czwg0n3pfkmpjphqv1jxfjlgkbziwsx-python-tox-1.4.3.drv' failed with exit code 1
-  # tox = buildPythonPackage rec {
-  #   name = "tox-1.4.3";
+  # Installs correctly but fails tests that involve simple things like:
+  # cmd.run("tox", "-h")
+  # also, buildPythonPackage needs to supply the tox.ini correctly for projects that use tox for their tests
   #
-  #   buildInputs = [ py virtualenv ];
+  # tox = buildPythonPackage rec {
+  #   name = "tox-1.7.0";
+  #
+  #   propagatedBuildInputs = [ py virtualenv ];
   #
   #   src = fetchurl {
-  #     url = "https://pypi.python.org/packages/source/t/tox/tox-1.4.3.tar.gz";
-  #     md5 = "3727d5b0600d92edf2229a7ce6a0f752";
+  #     url = "https://pypi.python.org/packages/source/t/tox/${name}.tar.gz";
+  #     md5 = "5314ceca2b179ad4a9c79f4d817b8a99";
   #   };
   # };
 
@@ -7284,10 +7303,10 @@ pythonPackages = modules // import ./python-packages-generated.nix {
   });
 
   virtualenv = buildPythonPackage rec {
-    name = "virtualenv-1.11";
+    name = "virtualenv-1.11.4";
     src = fetchurl {
       url = "http://pypi.python.org/packages/source/v/virtualenv/${name}.tar.gz";
-      md5 = "d1a7cf95b539a861a8215827f387c4eb";
+      md5 = "9accc2d3f0ec1da479ce2c3d1fdff06e";
     };
 
     inherit recursivePthLoader;
@@ -7309,6 +7328,27 @@ pythonPackages = modules // import ./python-packages-generated.nix {
     };
   };
 
+  virtualenv-clone = buildPythonPackage rec {
+    name = "virtualenv-clone-0.2.4";
+
+    src = fetchurl {
+      url = "https://pypi.python.org/packages/source/v/virtualenv-clone/${name}.tar.gz";
+      md5 = "71168b975eaaa91e65559bcc79290b3b";
+    };
+
+    buildInputs = [pytest];
+    propagatedBuildInputs = [virtualenv];
+
+    # needs tox to run the tests
+    doCheck = false;
+
+    meta = with stdenv.lib; {
+      description = "Script to clone virtualenvs";
+      license = licenses.mit;
+      platforms = platforms.all;
+    };
+  };
+
   waitress = buildPythonPackage rec {
     name = "waitress-0.8.7";