The number of gainfully employed software engineers/programmers that are active in open source is dwarfed by those whose output is mostly code for their employers. This is not necessarily a bad thing. Contributing bug fixes and feature requests here and there is fine, but you definitely want to get experience building something from the ground up, being able to talk about the decisions and tradeoffs, and seeing something through. These are all important characteristics and skills that employers value and will make you stand out.
There are downsides to running open source projects (time commitment, demands for your attention, unappreciation). However, if you're just looking to get your feet wet, many projects have issues and requests that are tagged in such way that they make sense for someone new to the project.
You missed it this year, but look at Hacktoberfest for inspiration.
Hacktoberfest 2016 - DigitalOcean