While we're on an R kick, Hilary Parker described how to create an R package from scratch, not just to share code with others but to save yourself some time on future projects. It's not as hard as it seems.
This tutorial is not about making a beautiful, perfect R package. This tutorial is about creating a bare-minimum R package so that you don’t have to keep thinking to yourself, "I really should just make an R package with these functions so I don't have to keep copy/pasting them like a goddamn luddite." Seriously, it doesn't have to be about sharing your code (although that is an added benefit!). It is about saving yourself time. (n.b. this is my attitude about all reproducibility.)
I need to do this. I've been meaning to wrap everything up for a while now, but it seemed like such a chore. Sometimes I even go back to my own tutorials for copy and paste action. Now I know better. And that's half the battle.