User Summary A simple two-player children's game inspired by the spirit and exploits of The Mad Scientists' Club book series. The object of the game is to be the first player to build a treehouse. The players each have their own team of four kids who are members of the Science-Mad Kids' Club. The players assign various actions for their kids to perform, including finding a suitable tree, gathering tools, and constructing various parts of the treehouse. The kids can be assigned to work alone, or in teams of two to four. The more kids assigned to a task, the greater the chance of success. There is no direct player interaction, just a competition to finish the task first. The Treehouse Building Game was originally designed in 2003, in conjunction with a re-reading of the Mad Scientists' Club stories, and was first released as a print-and-play design in 2017.