To enable the ability to manage competitons or contests - set terms, rules and actions, to create and manage competitions that can be available to registered users only, or all, etc.
 
create campaign. landing page for this?
create rules, ie entry via form on page, and start and end date of contest - also ability to extend if necessary or cancel.
system collates all users and conducts a random draw and selects a winner. or you can manually select a winner, ie based on 25 words or less style contests.
system publishes a winner on custom winner / results page, alerts winner by email automatically, and shows in customer's account under "my competitions" tab.
system archives older comps so you can still see who won what.
 
system able to create small widget draws such as a game: spin this "wheel" to see if you win something for that day only, ie $5 off any purchase made today only. or perhaps teh result is "sorry - you did not win anything this time, try again tomorrow / next week etc, better luck next time"
(system can also enable users to enter say once a week only, etc)
so it ca create a discount code that applies to their purchases only for that day. and only if they fulfill the rules, ie if they are registered users or part of a customer group ie VIP or perhaps you can allow all users whether logged in or not, to enter the draw..
 
Please also link points to competitions - you can win points awarded to your account ie first prize is 500 points, second prize is 200, etc.
 
both styles of competitions / contests would be appreciated and influence sales.