I think it’s a nice idea to contribute to open source project at least to just highlight this fact in your CV/resume when you are looking for a job.
- you show your level of commitment to something
- money is not the only motivator for you
- the code written by you is publically visible — you don’t need to explain what major design patterns you know, which technologies you are familiar with and how good you usually polish your code, that all can be seen
I think it can be compared with marriage. Remember that Alec Baldwin quote from “The Departed” movie?
Marriage is an important part of getting ahead: lets people know you’re not a homo; married guy seems more stable; people see the ring, they think at least somebody can stand the son of a bitch; ladies see the ring, they know immediately you must have some cash or your cock must work.