GeoLotto is a lottery based on location (similar to Postcode lottery), other than you pick a square (any square on the map). Prizes are then dropped on the map each week. You can select as many squares as you like, each costing you £1, with the odds of 1 in 20 being a winner, prizes range from £5 to £1,000,000.
The small little cheat I found is that if you deposit £10 after signing up with the promo code 'FREE1', you'll get an extra £1 to play with. Then withdraw your initial £10 and you have a nice free go at no cost!
I'll be happy to help if anyone needs a little advice :)