How can I sort options in an exposed views filter alphabetically?
j.Rowny's answer doesn't work because $form_state is not passed by reference.  You must actually modify the $form variable.  This worked for me:  

function yourcustommodule_form_views_exposed_form_alter(&amp;$form, $form_state) {
    foreach($form_state['view']-&gt;filter as $filter) {
        if($fid = $filter-&gt;options['expose']['identifier']) asort($form[$fid]['#options']);
    }
}