This is a great activity to get your students speak English and engage themselves in spontaneous conversations as well as to have them drill functional language and more particularly common and informal expressions formulated to show agreement, disagreement, opinions and requests.
Ideally you should do this on the occasion of somebody’s birthday, maybe your own, but it’s not absolutely essential. Having an interactive whiteboard or a computer and a screen will allow you to display instructions and expressions that you have prepared beforehand when needed. Otherwise you will be writing down the information on the board and then erasing it to make room for a new display of information.
If possible, play some background music to provide ambiance and bring one plastic cup for each student. You can also tell the students to hold an imaginary cup in their hands as they are having conversations.
The idea is to have an imaginary birthday party. Push the desks to the sides to create plenty of room in the middle for the students to stand up and mingle. Tell them that you will be displaying information on the board with tasks and relevant vocabulary for the tasks. They will have to strike up conversations with people around them and try to fit in the expressions they see on the board in the conversation exchanges. When you display new information and expressions, they will have to find somebody else to talk to and so on.
You should be engaged in conversations with the students as well and determine whether they are ready to see a new screen with new tasks. As a rule of thumb, keep a slide for as long as possible if the students are still having animated conversations.
Here are some suggested ideas but you should be adapting the tasks (and mostly the vocabulary) to best fit your students’ level. You may do this activity again with the same group of students by changing some of the tasks.