The first step in preparing brains to learn is to develop a "felt need" — a cognitive dissonance that leaves the student saying, "I just have to learn this!" We accomplish this through the 5 Ps of PBL . . . real-world, open-ended problems (problem-based) or challenges (project-based) that may also be place-based or profession-based.
At advanced stages of implementation, students themselves identify the problems or challenges they want to tackle (pursuit-based). The teacher then works to infuse the curriculum into those pursuit-based tasks.
The key is to launch a unit with the problem or challenge so that it drives a "felt need" to learn (as opposed to using it as a culminating activity).