An interesting take on why your employer should support you contributing to Open Source, and why contributing to Open Source doesn’t have to mean using personal time.
If you’re a programmer today, you’re almost certainly taking advantage of Open Source libraries. These libraries are saving you (and by extension, your employer/clients) much money, time and effort.
Therefore your employer/client should be ok with you contributing to the libraries during working hours. Obviously it will be easier if you focus on libraries that are in use for the project, and preferably addressing issues you’ve encountered, or adding features that are valuable to you.
The other benefit is exposure to other’s code, peer reviews, and all around improvement of your own design and coding abilities.
Something to think about, and talk with your employer/client’s about if they don’t currently allow it.