In this paper we propose the structure of an exploratory course in theoretical computer science intended for a broad range of students (and especially kids). The course is built on computational cards, a simple paper toy, in which playing cards are computational elements; computing machines can be defined, built and animated in a concrete way by disposing cards and moving objectified symbols on top of them, following formal rules. We provide details and examples of the kind of exercises to be used in such a course. Advantages of c-cards and motivations behind the course are also discussed.