This game can be a lot of fun when you have an animated class. You choose one word for each member of the class, write that word down on a piece of paper, but don't show it to anyone. You then explain to the students that they must speak for two minutes about a subject that you will give them. They must include the word or expression that you have written on the piece of paper in the talk. The students who are listening must guess what that word is. For example, a student has two minutes to talk about habits and customs in their country. They have 30 seconds to think about what they are going to say and are given a piece of paper with the word lightning on it. They must then try to incorporate the word naturally into their speech so that the other students can't guess what it is.
Some of the speeches that comes out of this are priceless! Try to make sure the words you give them and the subject they should talk about are very different.