When I show people the results it's completely different: I show the cards to a 50-something woman and she swoons like a 10-year old girl. I could be envious of people who know how to draw and to paint, but this project has led me to not take no for an answer and not to "not do" something because I don't know how to do it.
One key to side project success is to look at what people aren't doing as opposed to what they are doing. I am a bit envious of this one:
https://gregdavill.com/blog/d20
It's not really that much harder than the other things people light up with LEDs but the icosahedral geometry is unique.
Whenever there is explosive and widespread technological progress (say the World Wide Web) the right question to ask is "What took it so long?" (futurists in 1970 predicted something like the web would arrive in 1980 and in the form of Compuserve, Videotex, it did, but few people noticed.)
One long-term project I have is to do a sketch comedy performance with a video-game character projected in a mirror (see https://en.wikipedia.org/wiki/Pepper%27s_ghost); personally I think video-game characters are "overdeveloped"; I don't need to design or code one, I can get it "out of the box" and only need to code up the behavior. For whatever reason, these haven't escaped video games. That project is a personal moonshot for me because it involves the difficult problem of being funny, never mind reverse engineering a once-patented technology a German company used to deploy film mirrors. I was planning to do it in two years at first but my current schedule is five.
There are many things like that where all the pieces are ready but nobody has put them together. That's how you make a side project that's interesting, not "learn a new programming language".
I've had some pay off quicker than that, but the model for that is 20 hours a week for 4 weeks.
The "pay off" tends to be that someone realizes they just saw something they never saw before and they are so blown away an opportunity materializes.
Some examples:
* I got busted for anti-spam activities when I was in grad school, had to do "community service", decided to combine that with a tropical vacation, ended up developing one of the very first XML applications, wrote a book chapter about it, then took a trip to Sao Paulo to create a chat application aimed at Brazil.
* I built an "AI" that collected a million photographs that were almost perfectly tagged, made a web site based on it, and started getting better work
* I challenged myself to print something on my inkjet printer every day to keep it from drying out; along the way I got systematic about it, added support for QR codes, NFC, web publishing, etc. Made modifications to signage in my building and so far haven't gotten any complaints. Learned how to change the way people perceive things that already exist in the environment. This project encountered a "crisis" every month or so that caused big changes (printing the back first instead of the front caused me to not be afraid of using a lot of ink; that turned out to be important when I discovered that covering 30% of the wall with something 80% reflective has an uncomfortable effect on radiative transfer in a bright room.)
That last project will probably translate to more artistic endeavors, seducing people, and doing some kind of exhibition or performance even though I still don't know what that will be.