I've just heard about this on Money Saving Expert and it's pretty clever.
Basically it's a free to enter draw to win a minimum £30 daily. All you need to enter is your postcode and then you need to check daily to see if you've won. Any unclaimed winnings roll over to the next day. The site relies on high traffic and advertising so you won't receive any spam.
And the best bit is that the more of you that sign up the sooner the daily winnings increase to £40!