This paper introduces to Class-Card, a role-playing simulation allowing pre-service teachers to experience a large part of the instructional process, from planning, to post-active phases. The players first have to perform a cognitive analysis of the learning tasks of a lesson, then they are faced with disruptive events they react on, guided by theoretically-sound frameworks. We examined seven pre-service teacher students using Class-Card on five simulations. The results show that participants were engaged in rich decisions and verbal interactions about the events they were faced to. We contend that Class-Card is a promising way to attenuate the "reality-shock" novice teachers experience and help them build professional knowledge.