Hi,
I found very promising ICO (inicial coin offering) that has a good project and interesting promo reward system.
You only have to register using this link: http://authorship.com/contribute/?ref_id=O8175345
and click on "get 75 ATS" on the right side of the screen. It is worth 10$ in ATS Coins, which you will recieve in the middle of september. And if the project is a success (so far seems to be), the coin will have its value multiplied soon, so it can be 50 or even 100 dollars in another month or two.
This reward system is their way to let people know about ICO and you can also send some ETH to recieve much more of their tokens. But this 75 token reward is free for everyone.
All you need to have is an ethereum wallet (easily created in myetherwallet.com) and use its adress in the registration. The tokens will be added to your Ethereum account.
Hope you enjoy your reward! Me personally, I will hold to my ATS coins for a month or two, because the price is probably going to rise. If not, I will exchange it for Ethereum, which is on its way to the moon.