How to get people on guest list for club event?

[Kevin]

I am new to being an event manager,
Me and my business partner are renting out a club to host our own club event within it,
we have a Facebook page where we add people (so like a Facebook friend) we see it to be more convenient then a "like" page.. & we also have twitter... The problem we are facing is that despite the likes on our post and retweets on twitter people are not adding their names on guest list (guest list offers a cheaper entry fee and we feel like we can get a rough estimate on how many people are coming) we have 5 weeks until the event and we are becoming worried..

My question is how can we get people to text in/inbox/tweet their names for guest list?

(10 points will be awarded for best answer)

[Jake]

Add an in club giveaway contest offer, like CDs to winners who had signed up to the guest list.