Ask HN: One month off, any suggestions?

I am taking a month off from work in the next few weeks. In the past when I have taken some time off I have done app projects but the ROI on those has been quite small (other than the experience)

I am not sure what to do with all this free time (Restrictions: cant travel, have to be in town). I know that I want to disconnect from my day job.

Looking for suggestions on what you might do with this free time.