ITGS Higher Level (HL) students must take the paper 3 exam, which is based on a pre-seen case study and is described in the ITGS syllabus section 3.12 Information systems specific to the annual case study. For 2012, the case study is the "Theatre Booking System", examining how information technology is used in three theatre companies. Below are some resources I have found useful when teaching this case study. Feel free to use them and contact me if you have any comments or suggestions.
Note: The Theatre Booking System case study was for May and November 2012 only. The ITGS case study is updated each year. This case study is here for reference purposes only. The case study for May and November 2015 is An Investigation into Big Data.