So CryptoTab, chrome browser btc miner, has contest for 0.3btc 0.2btc and 0.1btc for first 3 places for members with most Refferals. I'm using CryptoTab myself for a month still don't know if they payout but it looks good to me...
If you would like to join https://getcryptotab.com/517915
Good luck ^^
