At any given time, I usually have a bunch of ideas for weekend/side projects that I can work on. The ideas can be generally be categorized into these:
1. Self Learning: Learning a new language/ technology/ framework
2. Work related: Learning/Doing something that would help you at work
3. Money: Projects that (you think) can make some money
4. Fun/Utility projects
These are just the rough categories that I can think of and there can be more/other ways of classification.
My question is based on your experience what should drive the decision of what kind of project to work on. What parameters apart from the type of project should impact this decision (time, effort, money...)