The built in lottery allows you to sell 100 tickets at which point it picks 4 winners at random and resets tickets to begin a new game automatically. In the admin side menu go to Site Functions > Lottery > Lottery Settings to enable the lottery and set your prizes.
(http://auroracoderz.info/acd_images/lottery_profit.jpg)
Lottery ticket price - when deciding this setting remember to consider if your prizes equal more than 100 x ticket price your site profit will be negative, meaning the draw has cost the site money. Generally owners want to make money here. If you have set your ticket price too low for your prizes to be covered the Site Profit in the Current Prize Data tab will be highlighted red and show a warning when hovered over.
(http://auroracoderz.info/acd_images/lottery_noprofit.jpg)
Below lottery settings in the admin side menu you will see ticket holders. This page has no functions other than allowing you to see who is playing the lottery, you cannot remove members tickets or decide the winning numbers etc.
(http://auroracoderz.info/acd_images/lottery_tickets.jpg)