In software development, side projects can be a source of personal fulfillment, career advancement, and often both. They're also the birthplace of a lot of innovation and commercial success. People are free to do whatever they please with their spare time, including not code at all. For those who want to embark on projects, I've noticed that a lot of folks are not really sure what they want to build in their spare time. To that crowd, I propose a path that does not get much attention: Science.
By science, I mean good old fashioned experimentation for the sake of discovery, as opposed to engineering with a "product" or "user" in mind. That path is great if you want to go there, but plain old research and experimentation can be just as impactful for the world, and perhaps a lot more fun. It does not get nearly as much attention in the age of "makers".
Instead of creating another calendar app or blogging platform, not that there's anything wrong with that, I encourage you to think about experimenting in software using the scientific method.
Types of experiments could include performance benchmarks, statistical analysis (perhaps using the BigQuery/GitHub dataset), or any attempt to validate a hypothesis you might have within our field.
I'm not imploring anything overly formal. I wouldn't even know where to begin with formal scientific publishing, but as a part of the software development community, there are a lot of ways to make an immediate impact with personal scientific research. One such way is to publish any interesting outcomes right here on dev.to. Those type of posts always get a lot of attention because they're inherently original. The software development community is always hungry for original research. It's also an area where inexperience can sometimes be a feature and not a bug, because you may be able to take a fresh look at an area of the field that others take for granted. As a means of standing out in a crowd of newer software developers, scientific research is a powerful one.
Science cannot always be justified as a business expense for a company, but since there is so much you can gain from it in terms of enjoyment and career advancement, it's easy to justify on a personal basis. If you hadn't thought to take the time to run some experiments, I urge you to consider it. The industry could use more of it and you'll have a lot of fun.