Ask HN: What should I do for the summer?

I'm a graduating software engineer from a Canadian university. My term will be over in April, and I'm pretty set on doing grad school. I'm in the middle of the process right now.

However, that still leaves the four months in between (May to August) free. I'm not sure what I should try and do for it. Work? Internship? Travel? Open source project? Start grad school early?

What are some thoughts from the experienced HN community?