How do we set today's date to be populated by default on a Date field when page loads?

Here is what I Tried:

    static $defaults = array(
        'GameDate' => 'date(\'Y-m-d\')'
    );

    public function GameResultForm() {

        $gameDate = new DateField('GameDate');
        $gameDate->setConfig('showcalendar', true);
        $gameDate->setConfig('dateformat', 'dd-MM-YYYY');
        $gameDate->setConfig('max', date('Y-m-d'));
        $fields = new FieldList (
            $gameDate
        );

        $actions = new FieldList(
            new FormAction('saveNewGame', 'Add New Game')
        );

        $form = new Form($this, 'GameResultForm', $fields, $actions,);
        $form->setFormMethod('POST', true);

        $data = Session::get("FormData.{$form->getName()}.data");
        return $data ? $form->loadDataFrom($data) : $form;

I also tried

        $gameDate->setConfig('setValue', date('Y-m-d'));

At first I thought you meant

private static $defaults = ['Date'=>'now'];

But reading it seems you are confused about DateField's configuration (min,max,1 field or 3[d,m,y], to javascript or not), and setting just about any FormField's value.

$datefield->setValue(date('Y-m-d'));

http://api.silverstripe.org/3.1/class-DateField.html#_setValue