Various forms of unplugged computer science activities have been proposed and employed at the student level in the past. However, there have been few studies of its effectiveness at the teacher level. Active Computational Thinking (CT) Games are unplugged CT activities that encourage physical movement. In school systems where computer science is not part of the curriculum, questions arise regarding how well teachers can learn the fundamentals of CT from Active CT Games, and how effective an Active CT Games approach could be in the classroom. In this paper, we present our findings from Active CT Games workshops with 60 pre-service primary school teachers (41 responses) who had no prior knowledge of CT. We adopted the Approximation of Practice method to evaluate and improve CT lesson plans during the workshops. Our findings show that, among teachers with no CT experience, and who already appreciate the value of learning through play, Active CT Games were positively received. Survey responses indicated that active approaches to teaching CT are appreciated for making learning fun and engaging, while also fostering problem-solving, communication, and critical thinking skills. The Approximation of Practice method proved to be effective, although improvements were suggested. We discuss teacher concerns such as the value of lesson plan scaffolding, and significant set-up and implementation times. Overall, these teachers, who had no prior experience in CT, reported high levels of confidence and enthusiasm in employing Active CT Games in the classroom after completion of the workshops.