Question: My website can only be accessed by authenticated users. How can I automatically make the author's name the user's name without giving users the option to input anything else in the name field?

Answer: 
Custom datepicker options are now supported (as of Date module version 7.x-2.6) by setting the necessary values with `#datepicker_options`. Alex's use case of a custom form element to display only future dates would look like this:

```
$form['date'] = array(
  '#prefix'=>t('When do you want to start the featured campaign?'),
  '#date_format' => 'Y-m-d',
  '#date_year_range' => '0:+1',
  '#type' => 'date_popup',
  '#weight'=>0,
  '#datepicker_options' => array('minDate' => 0),
);

```
As far as I know by default you do not have such option. The easiest way would be just to check it in validate function, and return an error if selected date is not from future.

On the other hand, a quick Google search returned for example this question - [how to restrict the user to enter only today to future dates. using datepicker](http://drupal.org/node/927582) - however you would need to test for yourself if it really works...