[wskinner]

I was in the same place as you. When I started my sabbatical I had some vague ideas, but mainly just planned to drive around the western US and experience the outdoors. After a few weeks I realized I missed thinking about technology, so I started doing the CryptoPals exercises (https://github.com/wskinner/cryptopals). I learned a lot, at my own pace, and didn't come back feeling like I wasted my time.

Those first few weeks of unstructured time were essential. Not framing the time as having to accomplish something is important - I found that my intrinsic motivation came back on its own anyway.