I would do something based on your own skills. What are you good at? What do you like doing outside school for instance? For example I was a journalist before I went into teaching so I would probablydo a mini-school newsletter via the school website or something like that.
We are going to vertical tutoring next term, and I need to offer an activity that will run for 2 consecutive 20 minute morning registrations, to 25 year 7-10's. Other staff are offering steel drums and drama workshops. Any inspiration out there?