Magento getBaseUrl

//BaseUrl
echo Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_WEB);
echo Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_JS);
echo Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_LINK);
echo Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_MEDIA);
echo Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_SKIN);

//BasePath
Mage::getBaseDir(‘media’)

Adding custom user meta to the user profile

<?php
class ee_user_meta {

function ee_user_meta() {
if ( is_admin() )
{
add_action('show_user_profile', array(&$this,'action_show_user_profile'));
add_action('edit_user_profile', array(&$this,'action_show_user_profile'));
add_action('personal_options_update', array(&$this,'action_process_option_update'));
add_action('edit_user_profile_update', array(&$this,'action_process_option_update'));
}

}

function action_show_user_profile($user)
{
?>
<h3><?php _e('Other Contact Info') ?></h3>

<table>
<tr>
<th><label for="something"><?php _e('Something else'); ?></label></th>
<td>
<input type="checkbox" name="guest_author" value="guest_author" <?php if(get_the_author_meta('guest_author', $user->ID)=='guest_author') echo 'checked'; ?> /> Guest Author<br />
<input type="text" name="something" id="something" value="<?php echo esc_attr(get_the_author_meta('something', $user->ID) ); ?>" />
</td>
</tr>
</table>
<?php
}

function action_process_option_update($user_id)
{
update_usermeta($user_id, 'guest_author', ( isset($_POST['guest_author']) ? $_POST['guest_author'] : '' ) );
update_usermeta($user_id, 'something', ( isset($_POST['something']) ? $_POST['something'] : '' ) );
}
}
/* Initialise outselves */
add_action('plugins_loaded', create_function('','global $ee_user_meta_instance; $ee_user_meta_instance = new ee_user_meta();'));
?>

Magento Admin Grid Default Column Types

Source File: app\code\core\Mage\Adminhtml\Block\Widget\Grid\Column.php

switch ($type) {
case ‘date’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_date’;
break;
case ‘datetime’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_datetime’;
break;
case ‘number’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_number’;
break;
case ‘currency’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_currency’;
break;
case ‘price’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_price’;
break;
case ‘country’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_country’;
break;
case ‘concat’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_concat’;
break;
case ‘action’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_action’;
break;
case ‘options’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_options’;
break;
case ‘checkbox’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_checkbox’;
break;
case ‘massaction’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_massaction’;
break;
case ‘radio’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_radio’;
break;
case ‘input’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_input’;
break;
case ‘select’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_select’;
break;
case ‘text’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_longtext’;
break;
case ‘store’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_store’;
break;
case ‘wrapline’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_wrapline’;
break;
case ‘theme’:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_theme’;
break;
default:
$rendererClass = ‘adminhtml/widget_grid_column_renderer_text’;
break;
}

here $rendererClass is the corresponding classes, who renders the output

For example the action column type:

app\code\core\Mage\Adminhtml\Block\Widget\Grid\Column\Renderer\Action.php