Let's say you have to persuade a student to participate in open source projects, what would you tell him?
And tech meetups are great, but it seems a waste of these few years to be going to them instead of meeting the people around college.
So I don't know. You tell me?
You participate in open source to fuel a passion. You do it as an outlet for your creativity. You do it to scratch an itch. You do it after looking at the landscape and saying "I could make it better".
If you're doing it for fame, glory, or job prospects, you won't contribute anything decent or noteworthy.
Looking at all the big projects out there has a tendency to give one a feeling of inadequacy; a feeling that one couldn't even muster up enough talent to contribute to such a project, let alone start one. It's really a matter of putting your ego and the fear of bruising it aside, and diving in. You might produce crap and it might be rejected, or it might not get used at all. But no successful person ever succeeds without failing many times first.
In a way, it's a lot like entrepreneurship. You need the fearlessness to say "I'm going to do this, no matter how foolish it seems." Great ideas always seem foolish compared to the wisdom of the crowd, but until you go in a different direction from them, nothing will ever change, and your life will remain dull and boring and pointless. Even if your idea really is foolishness (which often it can be), you'll still live the excitement of your new adventure. Life is too short to live safely.