Prior to running the exercise, I invented a detailed, fictitious but mathematically self-consistent cosmology for Zog. You can see a description of this cosmology, the initial briefing I showed the students, and the data I faked for them, at the web address listed in the appendix.
The students were very enthusiastic about this assignment, and almost all worked very hard at it. I was bombarded with questions after every lecture. Whenever the lectures covered some issue of direct relevance to the assignment, students perked up in class, began furious discussions and peppered the lecturer with detailed questions.
Several colleagues warned me that this assignment was too difficult for any of the students, but in the event all made substantial progress, and two groups essentially cracked the mystery.