I used to get up in the middle of the night to pursue my own technical investigation unfettered by corporate politics, stupidity, etc. It was a killer schedule (get home from w*rk around 6 PM, fix dinner, go to bed, get up at 11 PM, work on my own stuff until 3 AM, go to bed, get up at 5 AM, go to the gym, go to work, repeat...), however it was the only way that I could 'follow my passion'. After leaving the corporate world 9.5 years ago, I hit the ground running on my projects - no laying around doing nothing (sounds like torture).
Last year, I self-published my first book (contains the results from around 6 years worth of work). I'm doing the R&D for my second book now, and I have several other books I'd like to write. I don't care if anyone reads them, the satisfaction comes from producing something that meets my own standard for what constitutes excellence. All of my books involve material that requires a fair amount of software development R&D to develop fully, because that's really what I enjoy doing.
To save money, I handled all facets of book design & production myself. This was extremely labor-intensive, but interesting in its own right. I did hire a copyeditor, which was useful (I'm an engineer, not an English major). You can keep this development option in mind if one of your ideas matures into something that you think others might like to read. Good luck!