Head-Up Games [19,20] attempt to combine the technological benefits of modern electronic games with the social and physical advantages of traditional games. To demonstrate this concept, a Head-Up Game for 9- to 11-year-old children was designed and developed iteratively, with intensive involvement of children for play-testing. This paper describes and reflects on the game's design process and the implications regarding the concept of Head-Up Games. The final game, Stop the Bomb, was found to be physically and socially stimulating, understood and enjoyed by the target group, and preferred over a nonelectronic version of the game at first encounter. Categories and Subject Descriptors H.5.2 [Information Interfaces and Presentation]: User Interfaces