As per OzBargain:
My wife just bought the Sydney & Sydney North Entertainment Book, and when she registered her card it said that she was eligible for a free $50 Voucher to Use with Virgin Australia Holidays. I also noticed that the link was generic and managed to claim a $50 voucher for myself too. If you're not a member of Velocity Frequent Flyer it is free to join. Enjoy.
http://www.velocityfrequentflyer.com/content/Specials/entert…
From website:
To celebrate our partnership, Entertainment™ together with Velocity Frequent Flyer are giving you a $50 voucher from Virgin Australia Holidays.
To claim this special offer, simply register your Velocity membership number before 31 December 2015. Your voucher will be emailed to the address specified in your Velocity Account within 14 days.
Virgin Australia Holidays has an extensive range of holiday packages available, and there’s no minimum spend. Start planning your escape today at virginaustralia.com/holidays. there’s no minimum spend. Start planning your escape today at virginaustralia.com/holidays.