Viral Sweepstakes is probably the most powerful sweepstake application out there for Facebook. The base idea was to offer a ticket based sweepstake application so you can reward your users and customers with prizes. The user interface is simple.
You create a sweepstake at the admin interface and set an end date for it; you add the application to a Facebook page, a user navigates to the
application and connects to it and receives one or multiple tickets (explained later). When the end date is reached, the application will
automatically pick one or more winners or give you the ability to pick them manually, or export the tickets list and pick the winners anywhere and any way you want.
This is the whitelabel version which costs $797 and is the self-install version so you install it on your own hosting. It also has unlimited
sweepstake creation and 24h/12h/1h expiry notifications. Also an ad-free dashboard, adding tickets for users, multiple accounts, plus access to the entire code (so you can change the name etc) aswell as the base features.