Video Tutorial on Learning Git and GitHub
Here is a video by GitHub Training and Guides. You can tell that the presenter is passionate about teaching git. He shows you git starting with the command line console. Then it explains what GitHub is all about walking though a scenario on how anyone can start contributing to open source project. In the example scenario is two person (a master and a student) working on two different browsers. Video shows how the student forks the project and make contributions and then makes a pull request. The master can review and respond to such requests.