diff --git a/README.md b/README.md
index 8052d4d..f1b2c4e 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,7 @@
    [default.nix](./default.nix)
    * Remember to mark the broken packages as `broken = true;` in the `meta`
      attribute, or travis (and consequently caching) will fail!
+   * Library functions, modules and overlays go in the respective directories
 3. Add your NUR repo name and your cachix repo name (optional) to
    [.travis.yml](./.travis.yml)
    * If you use cachix you should also add your cache's private key to travis'
diff --git a/default.nix b/default.nix
index ada0825..46c4090 100644
--- a/default.nix
+++ b/default.nix
@@ -1,19 +1,21 @@
 # This file describes your repository contents.
-# It should return a set of nix derivations.
-# It should NOT import <nixpkgs>. Instead, you should take all dependencies as
-# arguments.
+# It should return a set of nix derivations
+# and optionally the special attributes `lib`, `modules` and `overlays`.
+# It should NOT import <nixpkgs>. Instead, you should take pkgs as an argument.
+# Having pkgs default to <nixpkgs> is fine though, and it lets you use short
+# commands such as:
+#     nix-build -A mypackage
 
-{ callPackage
-, libsForQt5
-, haskellPackages
-, pythonPackages
-# , ...
-# Add here other callPackage/callApplication/... providers as the need arises
-, ... }:
+{ pkgs ? import <nixpkgs> {} }:
 
 {
-  example-package = callPackage ./pkgs/example-package { };
-  # some-qt5-package = libsForQt5.callPackage ./pkgs/some-qt5-package { };
+  # The `lib`, `modules`, and `overlay` names are special
+  lib = import ./lib { inherit pkgs; }; # functions
+  modules = import ./modules; # NixOS modules
+  overlays = import ./overlays; # nixpkgs overlays
+
+  example-package = pkgs.callPackage ./pkgs/example-package { };
+  # some-qt5-package = pkgs.libsForQt5.callPackage ./pkgs/some-qt5-package { };
   # ...
 }
 
diff --git a/lib/default.nix b/lib/default.nix
new file mode 100644
index 0000000..53d6abe
--- /dev/null
+++ b/lib/default.nix
@@ -0,0 +1,8 @@
+{ pkgs }:
+
+with pkgs.lib; {
+  # Add your library functions here
+  #
+  # hexint = x: hexvals.${toLower x};
+}
+
diff --git a/modules/default.nix b/modules/default.nix
new file mode 100644
index 0000000..79e1d17
--- /dev/null
+++ b/modules/default.nix
@@ -0,0 +1,6 @@
+{
+  # Add your NixOS modules here
+  #
+  # my-module = import ./my-module;
+}
+
diff --git a/non-broken.nix b/non-broken.nix
index 18ae8b5..b9a2cf9 100644
--- a/non-broken.nix
+++ b/non-broken.nix
@@ -2,18 +2,20 @@
 # It's what gets built by CI, so if you correctly mark broken packages as
 # broken your CI will not try to build them and the non-broken packages will
 # be added to the cache.
+{ pkgs ? import <nixpkgs> {} }:
 
 let filterSet =
-      (f: s: builtins.listToAttrs
+      (f: g: s: builtins.listToAttrs
         (map
           (n: { name = n; value = builtins.getAttr n s; })
           (builtins.filter
-            (n: f (builtins.getAttr n s))
+            (n: f n && g (builtins.getAttr n s))
             (builtins.attrNames s)
           )
         )
       );
 in filterSet
+     (n: !(n=="lib"||n=="overlays"||n=="modules")) # filter out non-packages
      (p: (builtins.isAttrs p)
        && !(
              (builtins.hasAttr "meta" p)
@@ -21,5 +23,5 @@ in filterSet
              && (p.meta.broken)
            )
      )
-     (import ./standalone.nix)
+     (import ./default.nix { inherit pkgs; })
 
diff --git a/overlay.nix b/overlay.nix
index d9f98f8..082b038 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -4,12 +4,18 @@
 
 self: super:
 
-import ./default.nix {
-  callPackage = super.callPackage;
-  libsForQt5 = super.libsForQt5;
-  haskellPackages = super.haskellPackages;
-  pythonPackages = super.pythonPackages;
-  # ...
-  # Add here other callPackage/callApplication/... providers as the need arises
-}
+let filterSet =
+      (f: g: s: builtins.listToAttrs
+        (map
+          (n: { name = n; value = builtins.getAttr n s; })
+          (builtins.filter
+            (n: f n && g (builtins.getAttr n s))
+            (builtins.attrNames s)
+          )
+        )
+      );
+in filterSet
+     (n: !(n=="lib"||n=="overlays"||n=="modules")) # filter out non-packages
+     (p: true) # all packages are ok
+     (import ./default.nix { pkgs = super; })
 
diff --git a/overlays/default.nix b/overlays/default.nix
new file mode 100644
index 0000000..642fefa
--- /dev/null
+++ b/overlays/default.nix
@@ -0,0 +1,6 @@
+{
+  # Add your overlays here
+  #
+  # my-overlay = import ./my-overlay;
+}
+
diff --git a/standalone.nix b/standalone.nix
deleted file mode 100644
index cadb80a..0000000
--- a/standalone.nix
+++ /dev/null
@@ -1,9 +0,0 @@
-# You can use this file to build packages without adding the NUR namespace
-# or the overlay to your configuration.
-# It's also useful for testing and working on the packages.
-#
-# example:
-# nix-build ./standalone.nix -A mypackage
-
-with import <nixpkgs> {}; callPackage ./default.nix {}
-