I am now the small director of the propaganda department of the student union. Now our department plans to hold an activity for the whole school. If one person can best get the whole school involved.

Which university are you from? You can do activities according to students' advantages. For example, if you are from the School of Information Science, you can set up a computer clinic to solve problems for your classmates' computers for free. You are from the Conservatory of Music, hold a variety of singer competitions, and then go to the Social Union to find some clubs in this field to help you participate. Consider the venue, funds, personnel and time of the activity. If you can, find a sponsor, which will be more conducive to the event.