Ask HN: What would you do with 6 months of free time?

I'm graduating from college this month, and just accepted a job that I'll start in June-July. I was lucky enough to get a signing bonus as well as have some money saved up, and I want to put this gap time to good use.

I've got a few side projects that I've been putting off that I could work on, and a few hobbies that I could spend some time on (photography, for one), but I could do these things anytime.

Any particular places to travel? Any experiences that I could go and seek out in this time? Any other ideas?