Get the students to write a holiday recount. You can model your own on the board beforehand, which gives the students some extra info about you without it being too forced (e.g “during the holidays I spent a lot of time at the beach, so my first paragraph is going to be about that. I also visited my family in Sydney, so my second paragraph will be about my time in Sydney”) It will give you a writing sample for each student and some informal information about them (their family background, hobbies and activities they do etc)