Challenging yourself looks like a hard thing to do, if not impossible, after all, we are supposed to know ourselves so well that we cannot come up with something that would really challenge us. The reality is that we can, and should challenge ourselves continuously, not only workwise, but relaxation-wise as well to prevent falling into a rut and never growing.
What should we look for in a hobby?
It needs to be something that is not related to our job.
It needs to challenge our physical or mental abilities.
It needs to be something that is not connected with our daily activities.
It needs to be within our means.
It needs to be interesting, otherwise you will get tired of it easily and abandon it.
It needs to be challenging, however, not so challenging that your frustration level would be high.
Once we determine the hobby that you would like to pursue determine your next step:
Do you need to get supplies? If so, are the supplies easily obtained locally or do you need to order them?
Do you need to learn new skills? Can you learn from a book, or do you need to join a class?
Is the hobby one that requires specialized equipment? Does the equipment require special installation?
Can you join a class or a group?
If the hobby you choose is not something that you can easily adapt to do in the time you are not engaged in your everyday job, then a group might be the best option for you. For example, stained glass requires specialized equipment and supplies, not to mention the skills you will have to learn, indicating that the best way to stick to the hobby and be satisfied with the results is to join a class or a group in your area.
There are hobbies that can be rewarding and not demand our constant attention. One example of this is to select a hobby that can be left for a few hours or days and then come back to it and continue, such as putting together a large puzzle or a model.
Whichever hobby you decide to start stick to it and do it. Time you spend working on your hobby clears your mind from the daily demands and problems of your job and recharges your batteries to allow you to be even more effective in what you do every day.