d7dev.module

<?php
/**
* Implements hook_field_formatter_info().
*/
function d7dev_field_formatter_info() {
    return array(
        'd7dev_integer_duration' => array(
        'label' => t('Duration'),
        'field types' => array('number_integer'),
        )
    );
}
/**
* Implements hook_field_formatter_view().
*/
function d7dev_field_formatter_view($entity_type, $entity, $field,
    $instance, $langcode, $items, $display) {
    $element = array();
    $settings = $display['settings'];
    
    switch ($display['type']) {
    
    case 'd7dev_integer_duration':
    foreach ($items as $delta => $item) {
        //some simple math to covert the duration minutes to hours
        //and the remainder as minutes

//divide by minutes in 1 hour and get floor
    $hours = floor($item['value']/60);

//use the modulus to get the remainder of minutes
    $minutes = $item['value']%60;

//get greatest common denominator of minutes to convert to fraction of hours
    $minutes_gcd = gcd($minutes, 60);
    
//&frasl; is the html entity for the fraction separator, and we
// use the sup and sub html element to give the appearance of a
// fraction
    $minutes_fraction = '<sup>' . $minutes/$minutes_gcd .
        '</sup>&frasl;<sub>' . 60/$minutes_gcd . '</sub>';
//markup change color to red if hours > 0 (TRUE)
    $markup = $hours > 0 ? '<span style="color: #ff0000;">' . $hours . ' and ' . $minutes_fraction . ' hours' .  '</span>' : $minutes_fraction . ' hour';

//finally, return our formatted value as the markup for this field
//formatter
        $element[$delta] = array('#markup' => $markup);
    }
    break;
}
return $element;
}

function gcd($a, $b) {
    $b = ( $a == 0)? 0 : $b;
    return ($a % $b)? gcd($b, abs($a - $b)) :$b;
}