In order to create a report covering the cultural activities that took place in your fictitious department during the past year, you simply need to decide what you feel would be "cultural activities" that might have been made available or supported by the employer and/or employees of the department.
Cultural activities could include music, art, food, sports, religious observances, travel opportunities, and many other possibilities. You will need to decide if your report is going to include activities that were sponsored by your department (many companies underwrite community cultural presentations for public relations purposes), activities in which members of your department participated (highlighting department employees who were involved in community theater production, for example), or other possibilities. Some of your "report" may depend on how large the budget for those activities is! Sounds like it could be a fun assignment - dream!