Happy Birthdates is another free daily lottery website, in the same vein as FreePostCodeLottery (now called "Pick My Postcode").
My referral link: http://www.happybirthdates.com/invite.php?m=netherspark
Every day 10 winning 'birthdate codes' are drawn and each recieve £100 via Paypal. You do need to manually check and claim your prize by visiting the website, I don't know if they email to tell you that you've won the main draw but they definitely do if you win the smaller prize, as I was lucky enough to find out for myself.
There are a couple of caveats though. Firstly it's not just your date of birth that determines the draw, it's your "birthdate code" which includes your initials and both must be matched in order to win, this does reduce the chance of winning a bit. Secondly... ads. There are a lot of ads (it's how they fund the prizes) but sometimes when you're clicking through the main draw a large ad will spawn over half the screen and cover the results. It's pretty annoying when that happens and you generally have to wait about 3 seconds and then you can manually dismiss it.
I've yet to win the main draw myself, but I have won a random £10 prize. While the ads can get a little annoying it still only takes about 30 seconds each day to check the results, and despite the low chance of winning it still seems to be worth it.
In addition to the main draw there are more ways to win or to increase your prize:
100% Amazon Cashback:
The value of any purchases you make on Amazon, provided you either go through the Happy Birthdates website or manually add the purchase details after the fact, will be added to your prize fund. And when/if you win one of the main draws you will recieve the total of all the money you've spent on Amazon plus the £100 prize. There doesn't seem to be any limit on how high you can push the prize.
Aside from the main draw, if you visit the site regularly you will be eligible for the randomly selected 'loyalty prize' of £10. I was surprised to win this as I didn't even know they had this extra draw.
You can also give out your own referral code and if any of the people you've referred win the main draw YOU win as well - you will both get £100. Everyone gets 10 chances to win each day, and so if you refer 10 people you would have 110 chances to win each day.