Heads up! This blog post hasn't been updated in over 2 years. CodePen is an ever changing place, so if this post references features, you're probably better off checking the docs. Get in touch with support if you have further questions.

It’s always awesome to see CodePen pop up in videos of presentations around the world!

Brad Westfall at HTML5DevConf 2014

And screencasts as well:

Martin Wolf screencasting

You’re of course free to use CodePen in any capacity like this, and in any view you please, but we might suggest Presentation Mode for giving you a bit more screens pace and the ability to adjust things like font-size quickly on the fly.