Each pupil has a sheet of paper with different categories on it. I usually use boy, girl, animal, food / drink, country, verb and adjective. You can use other categories depending on the level of your class (maybe clothes, colours, sports etc.).
Then say “go” to one pupil, who says the alphabet in his / her mind. Say “stop” and whichever letter they are at, is the first letter for all of the categories.
The pupils then have to think of a boy’s name, girl’s name, animal, verb (etc.), which starts with that letter.
Give them a certain time limit, then find out the results. The pupils tell you what they have for each category (if anything). A pupil who has a unique entry (i.e. no other pupil has the same word) gets 2 points. 1 point is given to words that two or more pupils have.
For example, if the letter was C, most of the pupils would probably choose CAT as their animal, but a pupil who has thought of a more difficult or less common animal, like CROCODILE, will get the bonus point if no other pupil has the same animal. I teach ESL in China, and it is a great game.