The number one thing I can recommend to increase your chances of finding a job is to get to know as many people as you can, some of whom might, at the very least, think of you when they hear of a job. Because there is a good chance those people know people who know other people and somewhere in that web of relationships there might be a job for you.
No language or project you contribute will come anywhere close to touching that.
What's that you say? You don't like dealing with people and you just want to push 1's and 0's around?
Well no shit. Most of us are like that, which is why we ask questions about what acronym we can learn to help us find a job. Of course nobody hires an acronym even though it appears that way. They hire people. They also tend to hire people they heard about from other people.
Now learning a new language or building a Zelda-like game sounds like a lot of fun. It might even look good on your resume. But let's ponder that for a second. What does a Zelda game you built by yourself tell me about your ability to build a form on an enterprise application that runs on Windows and talks to an Oracle database. What does it tell me about ability to take direction and work with a team?
All of this is irrelevant because I am never going to even see your resume. Because you mailed it off to my newspaper ad just like ever other random graduate from a JavaSchool. It ends up in a stack that I get through as fast as possible picking off the acronyms I like and shit canning the others. And if, by some miracle, I do pick yours then in the interview I might be suitable impressed by your contribution to the open source Tiznak project or that you were the 4,000th Zelda clone on SourceForge to hire you. That is a big maybe in my opinion.
But more likely I am going to go with the guy who knows the girl who I met at the Scheme user group meeting.
So my suggestion is go meet the girl who is going to meet the me at the Scheme user group meeting. Figure out a way to contribute to communities of people who could possibly help you. Don't go in expecting that help but do not be afraid to ask for it.
And if people-facing is just not your thing well welcome to the party, you are not the lone ranger. But just because you suck at something is no reason not to fix it. You say you have free time, then spend it learning how to interface with people. Time spent perfecting that skill will pay way more dividends than Scheme.