Valid only on the 12th of May on the two sessions listed below:
10am: Flight of the Butterflies 3D
11am: Titans of the Ice Age 3D
Simply download the voucher and buy one other ticket, either adult or child, and mum will receive free entry to either of the two film sessions.
$5 parking nearby also available if you want to go on mother's day.
http://www.ozbargain.com.au/node/102579