Android
https://play.google.com/store/apps/details?id=org.gamatech.andro…

Login or register
Go to the movie ticket section
Add a movie ticket for Detroit
On that section, select 3 contacts to invite to the movie as well, and add the movie ticket to your cart
You should see the Free ticket offer applied in your cart
You need to have a credit card in your atom account to make this work