diff --git a/calendar.pl b/calendar.pl
new file mode 100644
index 00000000..f724d344
--- /dev/null
+++ b/calendar.pl
@@ -0,0 +1,25 @@
+$ModulesDescription .= '<p>$Id: calendar.pl,v 1.1 2004/01/30 01:45:27 as Exp $</p>';
+
+*OldCalendarGetHeader = *GetHeader;
+*GetHeader = *NewCalendarGetHeader;
+
+sub NewCalendarGetHeader {
+  my $header = OldCalendarGetHeader(@_);
+  my $cal = Cal();
+  $header =~ s/<div class="header">/$cal<div class="header">/;
+  return $header;
+}
+
+sub Cal {
+  my $cal = `cal`;
+  return unless $cal;
+  my ($sec, $min, $hour, $mday, $mon, $year) = gmtime($Now);
+  $cal =~ s|\b( ?\d?\d)\b|{
+    my $day = $1;
+    my $date = sprintf("%d-%02d-%02d", $year+1900, $mon+1, $day);
+    my $class = ($day == $mday) ? 'today'
+              : ($IndexHash{$date} ? 'exists' : 'wanted');
+    "<a class=\"$class\" href=\"$ScriptName/$date\">$day</a>";
+    }|ge;
+  return "<div class=\"cal\"><pre>$cal</pre></div>";
+}