Contributing to open source is, as the arihant answered, a hype. Don't do it. It is a form of slave labur where you give your knowlidge for free (it is not about giving your coding skills) you give your expertise for free to anyone, typically different companies, to profit from your work. Without ever paying you they craft their profit from what you have made. This kind of attitude brought developers wages down for more then half from 10-15 years back where instead of paying for developers work, everyone was profiting(not the developers - everyone else, from system admministrators to the lousiest company) from "off the shelf" code.
To explain it for idiots: when I need someone to pave my backyard, try to ask someone to make it for free while you will give him references. Absolutely no one will ever do it. Only the developers are stupid enough to do it. It is humiliating, it is stupid, but we are still doing it... for the fame? For the "pie in the sky"? Don't know, but surely is spitting in our own food.
(And now the downvoting begins from those who profit from our free labour)