For Software Freedom Day. Touches on aspects of contributing and the basic skills involved/needed, some examples and the demo repository used.
View presentation at https://open-source-tott.appspot.com
I won't begrudge you if you decide to view the presentation here though it's not perfect. I've tried to make it better.
Click on the below and hit f to view in fullscreen. Press Enter, space , → to advance; Backspace, ← to go back.