I was looking for some way of adding a selectbox in the navigation so that one could pick a category and then get directed to the page with all products in that category. After much looking I found this page, that did sort of what I wanted. Customizing I got the following code for the top block in Magento.
<div class="header-nav-container"> <div class="header-nav"> <select class="browser_box" name="browser" onchange="location = this.options[this.selectedIndex].value;"> <option>Please select a category...</option> <?php $obj = new Mage_Catalog_Block_Navigation(); $store_cats = $obj->getStoreCategories(); $current_cat = $obj->getCurrentCategory(); $current_cat = (is_object($current_cat) ? $current_cat->getName() : ''); foreach ($store_cats as $cat) { echo '<option value="'.$this->getCategoryUrl($cat).'">'.$cat->getName()."</option>"; } ?> </select> </div> </div>