Open source projects represent, code bases being worked on by multiple people for a common goal! The google definition is open source - denoting software for which the original source code is made freely available and may be redistributed and modified.
Open source projects help accelerate innovation , why not contribute? You also learn a'lot during the process of contributing.. so its a win win situation! Our first open source project launched was toolbox.io - created by Rise Customs. Here we plan to display everyday, computer based tools (calculator, calendar, etc) and display them in the most elegant way possible! This project was created with ReactJS, Facebooks open source language ;0 see what we did there!
We urge you to do your own investigating on, open source projects and jump head first into something while you have the time, contributing is a great feeling.