This is my fovourite activity-interviewing. After finishing one lesson, I often have students do a project by interviewing their friends. They ask questions and use structures that they have learnt to have more answer from friends. However it is suitable for those who are in higher level. This's simply due to the fact that students have to pronounce accurately so that others can hear questions and they have to be good at grammar to give right questions and answer. But I apply this activity for whole class because it's time for students not only in high level but also in lower level to practice speaking. It helps them make progress day by day. For eaxmple, after learning about feelings (happy, sad, fine, great), I ask students to interview their friends questions: "What's your name?", "How are you?" and take note in the table.