diff --git a/src/HydraFrontend/lib/HydraFrontend.pm b/src/HydraFrontend/lib/HydraFrontend.pm
index 68688a67..f5e67d7a 100644
--- a/src/HydraFrontend/lib/HydraFrontend.pm
+++ b/src/HydraFrontend/lib/HydraFrontend.pm
@@ -13,7 +13,10 @@ use Catalyst qw/-Debug
                /;
 our $VERSION = '0.01';
 
-__PACKAGE__->config( name => 'HydraFrontend' );
+__PACKAGE__->config(
+    name => 'HydraFrontend',
+    default_view => "TT"
+    );
 
 __PACKAGE__->setup();
 
diff --git a/src/HydraFrontend/lib/HydraFrontend/Controller/Root.pm b/src/HydraFrontend/lib/HydraFrontend/Controller/Root.pm
index 681c9243..05b8ce9b 100644
--- a/src/HydraFrontend/lib/HydraFrontend/Controller/Root.pm
+++ b/src/HydraFrontend/lib/HydraFrontend/Controller/Root.pm
@@ -3,6 +3,7 @@ package HydraFrontend::Controller::Root;
 use strict;
 use warnings;
 use parent 'Catalyst::Controller';
+use HydraFrontend::Helper::Nix;
 
 #
 # Sets the actions in this controller to be registered with no prefix
@@ -391,7 +392,13 @@ sub closure :Local {
     my $product = $build->buildproducts->find({productnr => $productnr});
     return error($c, "Build $buildId doesn't have a product $productnr.") if !defined $product;
 
-    return error($c, "Not yet implemented.");
+    return error($c, "Product is not a Nix build.") if $product->type ne "nix-build";
+
+    return error($c, "Path " . $product->path . " is no longer available.") unless HydraFrontend::Helper::Nix::isValidPath($product->path);
+
+    $c->stash->{current_view} = 'HydraFrontend::View::NixClosure';
+    $c->stash->{storePath} = $product->path;
+    $c->stash->{name} = $build->nixname;
 }
     
     
diff --git a/src/HydraFrontend/lib/HydraFrontend/Helper/Nix.pm b/src/HydraFrontend/lib/HydraFrontend/Helper/Nix.pm
new file mode 100644
index 00000000..908aa990
--- /dev/null
+++ b/src/HydraFrontend/lib/HydraFrontend/Helper/Nix.pm
@@ -0,0 +1,14 @@
+package HydraFrontend::Helper::Nix;
+
+use strict;
+
+
+sub isValidPath {
+    my $path = shift;
+    $SIG{CHLD} = 'DEFAULT'; # !!! work around system() failing if SIGCHLD is ignored
+    return system("nix-store --check-validity $path") == 0;
+}
+
+
+1;
+
diff --git a/src/HydraFrontend/lib/HydraFrontend/View/NixClosure.pm b/src/HydraFrontend/lib/HydraFrontend/View/NixClosure.pm
new file mode 100644
index 00000000..696bce63
--- /dev/null
+++ b/src/HydraFrontend/lib/HydraFrontend/View/NixClosure.pm
@@ -0,0 +1,26 @@
+package HydraFrontend::View::NixClosure;
+
+use strict;
+use base qw/Catalyst::View/;
+use IO::Pipe;
+use POSIX qw(dup2);
+
+sub process {
+    my ( $self, $c ) = @_;
+    
+    $c->response->content_type('application/x-nix-export');
+    $c->response->header('Content-Disposition' => 'attachment; filename=' . $c->stash->{name} . '.closure.gz');
+
+    my $storePath = $c->stash->{storePath};
+
+    open(OUTPUT, "nix-store --export `nix-store -qR $storePath` | gzip |");
+
+    my $fh = new IO::Handle;
+    $fh->fdopen(fileno(OUTPUT), "r") or die;
+
+    $c->response->body($fh);
+    
+    return 1;
+}
+
+1;
diff --git a/src/HydraFrontend/root/build.tt b/src/HydraFrontend/root/build.tt
index 082c24f2..d65fc0fb 100644
--- a/src/HydraFrontend/root/build.tt
+++ b/src/HydraFrontend/root/build.tt
@@ -1,5 +1,6 @@
 [% WRAPPER layout.tt title="Hydra Overview" %]
 [% PROCESS common.tt %]
+[% USE HTML %]
 [% USE date %]
 [% USE mibs=format("%.2f") %]
 
@@ -205,6 +206,24 @@
         <img src="/static/images/nix-build.png" alt="Source" />
         Nix build of path <tt>[% product.path %]</tt>
       </a>
+      [<a class="productDetailsToggle" href="javascript:">help</a>]
+      <div class="help productDetails">
+        <p>If you have Nix installed on your machine, this build and all
+        its dependencies can be unpacked into your local Nix store by
+        doing:</p>
+        
+        <pre>$ gunzip < [% HTML.escape(build.nixname) %].closure.gz | nix-store --import</pre>
+
+        or to download and unpack in one command:
+
+        <pre>$ curl [% c.uri_for('/closure' build.id product.productnr) %] | gunzip | nix-store --import</pre>
+        
+        <p>The package can then be found in the path <tt>[%
+        product.path %]</tt>.  If you get the error message “imported
+        archive lacks a signature”, you should make sure that you have
+        sufficient access rights to the Nix store, e.g., run the
+        command as <tt>root</tt>.</p>
+      </div>
       
     [% CASE "file" %]
       <a href="[% c.uri_for('/download' build.id product.productnr product.name) %]">
diff --git a/src/HydraFrontend/root/hydra.css b/src/HydraFrontend/root/hydra.css
index 7c2a641d..6ba2976f 100644
--- a/src/HydraFrontend/root/hydra.css
+++ b/src/HydraFrontend/root/hydra.css
@@ -205,6 +205,17 @@ div.jobset-edit h3, div.jobset h3 {
     margin-top: 0.5em;
 }
 
+div.help {
+    border: solid black 1px;
+    padding-left: 1em;
+    padding-right: 1em;
+}
+
+div.help pre {
+    padding-left: 1.5em;
+    color: #400000;
+}
+
 
 /* Sortable tables */