If it's to gain brownie points for your CV, it's quite likely that you'll get nowhere, because that's a motivation right along with "earn money".
The difference to just getting a random software development job for earning money is that at the random job, you will be in a team where tasks will naturally flow towards you. In a random open source project, this will not be the case. So most people will not stick with it unless they have a better motivation for contributing to the project in the first place.
So try to find a project that you find interesting first. You should actually be able to find many of those if you're into software development, and then take a look at the communities yourself.