This is one we do twice a year. We nominate a month (suggested months are March and September) as a bring-a-friend month, and we give a ticket to everyone that brings a friend along to try a class out. We give 10 tickets to them if their friend joins.
Every ticket goes into a barrel or hat, and at the end of the month we make a big announcement with the winner.
The PlayStation or Xbox should be displayed for the entire month. You should hand out free passes (3-day membership experiences) to each and every one of your students in the first week of the month.
Promote this via Facebook and Instagram. Put posters up in your club.