If you don't like to gamble, you can also invest in bitcoin gambling sites. But that is also not without its risks.

Another opportunity to earn bitcoin will happen when Open Bazaar opens up. Currently it is in testnet phase where they are finding and fixing bugs, like a alpha or beta testing I suppose. Open Bazaar is like ebay where people can buy and sell anything using bitcoin, but without all the fees ebay nickel and dimes you to death with. Lots of people make a living and/or supplemental income using ebay. Open Bazaar looks to give people the same opportunity using bitcoin.