How-To: wpdb Insert Record With Date

I am writing a plugin where I need to pre-load some data in the custom tables that I create upon Activation. My inserts have run fine thus far until I attempt to insert a record with a DATE datatype. Can someone please tell me what I have wrong here?

Database Table Definition:

$sql =  "CREATE TABLE IF NOT EXISTS " . $wpdb->prefix.SSM_ACADEMIC_YEAR_TABLE. " (
                  id mediumint(12) NOT NULL AUTO_INCREMENT,
                  academicyear VARCHAR(200) NOT NULL,
                  begin_date date NOT NULL,
                  end_date date NOT NULL,
                  created_date TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                PRIMARY KEY (id));";

    $wpdb->query($sql);

Database Insert:

$current_year = array(
            'academicyear' => '2012 - 2013',
            'begin_date'   => date('Y-m-d', '2012-08-14'),
            'end-date'     => date('Y-m-d', '2013-05-31')
        );

        $wpdb->insert($wpdb->prefix.SSM_ACADEMIC_YEAR_TABLE, $current_year);

I have tried many different methods like just using => ‘2012-08-14’ but that doesn’t work either. I’m sure there’s some syntax I am either missing or I have wrong.