OpenIntro’s (openintro.org) mission is to make educational products that are free and transparent and that lower barriers to education. The products include textbooks (in print and online), supporting resources for instructors as well as for students. In this talk we will discuss how the OpenIntro project has shaped and grown over the years, our process for developing and publishing open-source textbooks at the high school and college level, and our computing resources such as interactive R tutorials and R packages as well as labs in various languages. We will also give an overview of our project organisation and tooling for authoring, collaboration, and maintainence, much of which is built with R, R Markdown, Git, and GitHub. Finally, we will discuss opportunities for getting involved for educators and students contributing to the development of open-source educational resources under the OpenIntro umbrella and beyond.