The British are the worst language learners in Europe! This is according to a survey published by the European Commission. Only 38% of British people can speak a foreign language, as against the European Union average of 56%.
The activity should work at most levels above elementary, as long as your students have some knowledge of past tenses, but it works best when they also know past continuous / progressive too. All you need to get things started is a sheet of plain paper for each pair of students.