Towards that end, I employ self-directed learning projects in several classes I teach, where learners are afforded several weeks of in-class time (in lieu of any formal curricula) to choose projects they want to work on. They can generally choose anything that interests them as long as it aligns with course goals, and are responsible for checking in with me (in writing and in person) during their projects. Once comlpeted, students exhibit their projects to their peers, get (and give) feedback on each other's projects, and grade their own projects based on their experience with the project and feedback received.
Here is a document further explaining how I structure these projects.