From all this answers I see we can choose between ponzi schemes, gambling, trading. But more or less everything of this things is a gambling, so maybe its best thing to try it. Find some good strategy, or you can check google for some tutorials and sites offering some winning strategies.
i think if we know about investment in gambling, its a good investment but you still be careful when you want to make any investment. for me, i am lending some amount of bitcoin into market exchange and i think i am making some of bitcoin and i can see its really grow although its not a big amount.
Investment in gambling is good starting if you are saving bitcoins while waiting for the price increases , But make sure that you are going to invest on the right investment website that can live long run investment. Definitely although bitcoin price will increase but not that big enough but atleast we really can make profit while waiting.