Research "employment" options for students graduating midyear?
My experience is limited to anecdotes. What I have generally seen is that students usually attempt to get either a paid industrial internship or an paid/unpaid research internship with a particular research group. 

In fact, I have been mentoring an undergraduate who is graduating in the middle of the semester and is preparing to spend the next 6 months working as a research assistant (paid ~$15/hour) for a research group in our university before joining a prestigious PhD program in another university.