Twenty Questions is a simple game which can be played in class with minimal preparation. It is ideal for practicing both vocabulary (notably semantic fields) as well as making questions.
Collect a group of pictures or photographs with different objects on them. (You can laminate these to make them longer lasting of course.)
The objects you choose should be of the right level and subject matter for the class.
Playing the Game
Divide the class into small groups of, say, three. One person from each group is given a card and the others have to guess what is depicted on it. However the answers to their questions can only be Yes or No.
A typical dialogue might go like this:
S1 is holding a picture of a golf club.
S2: Is it an animal?
S3: Is it a man-made thing?
S2: Would you find it in an office?
S3: Can you wear it?
S2: Is it bigger than a loaf of bread?
S3: Do you use it for fun?
S2: Is it round?
S3: Is it part of a game?
S2: Is it a cricket bat?
S3: Do you use it outside?
S2: Is it used in sport?
S3: Is it a golf club?
Depending on the level of the class you can make the game easier by telling the students the semantic field which the object belongs to or starting off by giving a clue as to the object, e.g. whether it is an animal, food, etc.
Variations can include famous people or places, abstract ideas for advanced classes and so on.
Semantic Fields in TEFL– lexical fields explained.