Build a cryptocurrency exchange similar to [url removed, login to view] or wex.nz. The website uses API and works with other exchanges in order to trade cryptocurrencies.
The availible cryptocurrencies will be Bitcoin, Litecoin, Monero, Dash, Ethereum and a few more.
You will need to be able to design a good look and secure system.
I will be paying once the job is done, because of previous scammers, I will be paying after the job is done.