You could theme your sweepstake around a sporting event such as Wimbledon or the World Cup or it could be a one-off event such as The Grand National. 

Alternatively you could choose a television show with weekly eliminations such as The X-Factor, Great British Bake Off or The Apprentice.

Draw your sweepstake before the event starts and charge a small fee per entry, keep people engaged with regular updates and remember to give a prize to the winner!