Using the Date Widget with Drupal's Form API

I recently had to use the Date module in a custom booking form that was constructed using Drupal's awesome Form API. Now I'm sure someone is going to come along and prove me wrong but I couldn't find any documentation on the available widget types, form properties or much of anything to be honest. I did find a few wrong examples that were doing some weird hacks like overwriting #process. Here are a few examples to get you going with the Drupal Date widget that I found by digging through code, looking at other modules and just outright guessing. Below shows how to:

1. Select box Drupal date widget
2. Set the date format
3. Set the date year range
4. Set the date minute increment

<?php

$form['custom_date_field'] = array(
     
    // The drop down select widget.     
    '#type' => 'date_select',

    // This follows PHP's standard date letters. This is the format
    // that will be outputted.
    '#date_format' => 'd m Y H i',

    // The first number is how many years to go back, and the second forward.
    '#date_year_range' => '-0:+1', 

    // The minute increment.
    '#date_increment' => '15',
);

?>

As I find any more attributes and their interesting formats i'll be sure to post back.