Answer some surfing questions so we can assess your knowledge and skills, and we’ll send you a surfer’s cheat sheet.
You could come up with a series of questions—like when is the best time to surf, what to wear, how long to wait for a wave, and so on—and then assign the person a rank (beginner, pro, etc.) based on their answers. To get them to leave their contact details, you could offer an interesting guide or cheat sheet: "You're a beginner, but we love beginners and will teach you everything—leave your number, and we'll send you a handy guide.