category filter

Despite following the tutorials, researching and trying numerous methods I cant seem to show a single category in a set. Where am I going wrong?

I did manage to display the cat heading but I need to show all items listed in the category.

This gives me all items in my activities set but I need to list those that are just under one category. i.e..hem

<?php

 perch_content_custom('Activities', array(
  'template' => 'act-list.html',
  'page'=>'/activities.php',
   'category' => perch_category('activities/'.perch_get('cat').'/')

));

?>