We're engineers and scientists, and we take pride in being very rational in our decision making. But are we really that rational? While over the years we've identified some of the strategies and tactics that software people use during the development of new, bold, large software-intensive systems—divide-and-conquer, brainstorming, reuse, and others—we also observed some strange tactics, biases, and reasoning fallacies that creep in at various stages and pervert the software development process. They go by simple, funny, or fancy names: anchoring, red herring, elephant in the room, post hoc ergo propter hoc, non sequitur, argumentum verbosium, and so on. I present an illustrated gallery of these games and show how they sometimes combine to be subtle but elaborate political ploys. Many of these games have dramatic effects on software endeavors: rework, budget overruns, and failures. To label a decision or judgment a reasoning error, we need to have a standard, a performance norm. But as software development has become essentially a social activity, our performance norms are unlikely to be ultra-rational and are tainted with emotional baggage. By better understanding these games and the underlying mechanisms, we may mitigate their effects.