Create space game and implement lottery in it.
I think idea is good, but before you create lottery ask yourself one question - would you pay 2$ for car lottery ticket in new site and share your personal information?
IMO it's better to pay in bitcoins.
In the space game there will be kind of lottery. If you will attack another player's ship and win, you will receive some value of his ship and hold.
You will be able to upgrade your ship, and it will cost more. With bigger weapons your ship will have higher chance to win. But you will lose more expensive ship if you will lose.
Maybe game concept will include the cost for the fuel. You will be able to find fuel free too sometimes.
The money from the fuel will be used for garbage.
If you will find something interesting in garbage (for example, metal) you will be able to sell it for some BTC.
If you will find brilliants you can sell if for a really good price (like 10 BTC).
In the lottery the only winner should share his personal information. Maybe 1 ounce gold coins and BTC equivalent will be also as a prizes.