Cardboard, a common maker space material, is inexpensive, readily available, and durable. It is also easy to manipulate. It can be folded, cut, painted, and taped or glued together. Caine’s Arcade, a video featuring Caine Monroy’s cardboard arcade, inspired countless cardboard maker space events and engineering design challenges (see Online Resources). For several years, we held multi-grade level cardboard arcade engineering design challenges. Participating students designed and built cardboard arcade games that were displayed in school hallways. However, this year, we wanted to elevate our K–5 grade cardboard engineering challenge to support other school subjects such as technology, language arts, math, and social studies and we wanted it to be interactive—not just a display. We decided that a “cardboard city” engineering challenge might provide the interactive and integrative opportunities we wanted.