Alternatively, they can come in handy in the first lesson after the summer holidays to activate your students and revise vocabulary.
Both activities are very simple and your students won't need anything but a pen and paper. They are adaptable to any level and age and there is no preparation needed. Once you instruct your students what to do, you can withdraw completely and see the magic happen. Both activities are suitable for groups and larger classes (the minimum would be 4 students), especially if you want to increase student talking time and help your learners improve speaking fluency. Although I'm sure the activities won't be completely new to you, each of them includes a tweak you haven't probably considered before.
Give each student a small piece of paper. Ask Ss to choose a certain number of English vocabulary items from their notebooks/vocabulary lists at the back of the book/whatever (ideally 12 -15 words). Each student will presumably end up with a totally different set of words, which is desirable. Ss stand up and start mingling, playing a game similar to Bingo. The aim is to get rid of all the items on the list. Student X meets Student Y and describes one word from the list. When Student Y guesses the word, Student X can cross it off/tick it. They change roles. When Student Y crosses off one word too, they swap the lists. At this point, student X has Student Y's list and finds another player, Student Z, for example. Ss could obviously play without constantly swapping the lists, but they would only see the words they have chosen. It's more challenging if they are encouraged to describe the words other Ss have picked plus the vocabulary revision effect is much bigger. The one who ticks the last word on the list they're currently holding is the winner and shouts 'Bingo!' Sometimes Ss are excited about the fact that they've ended up with their original lists, which is fine.
Ask Ss to get into pairs. Give each pair a large piece of paper (A4). Demonstrate the activity with one student at the board. For starters, describe a simple word, such as *cat*. When the student at the board guesses the word, he writes it down. Now, it's his turn to come up with a word but it must start with the last letter of the previous word, i.e. the letter t. When you guess what the student means, you write it down. The game goes on for a certain amount of time, which is totally up to you. The winner is the most productive pair in the class, i.e. the pair with the most words recorded.
As a follow-up activity, I usually ask Ss to look at their lists again and put the words into categories (or invent a category for each item). This is very useful because it actually increases the amount of vocabulary practiced. For a simple word like *chair*, Ss will find categories such as furniture, wooden objects, things to sit on, etc. and thus will revise even more lexis. Lots of useful connections will be created during this stage. Remember that all the input has been generated by the students, not the teacher. One student's output becomes another student's input.
The fact that students can choose their own words to work with is highly motivating. Another motivating factor is the game element, but your students will quickly forget that it's a competition because they will fully concentrate on the task, i.e. to grasp/find and define a word. Also, they need to find strategies which help them define a word as quickly and effectively as possible. Although in Activity 1 they play individually, the opponents actually become allies. For instance, when talking to a weak student, a strong student will have to adjust the definition to make it easy to understand. In other words, they all need to cooperate with one another in order to successfully complete the task.
Note: These ideas were originally shared on my own blog (https://hanatichaeltblog.wordpress.com/2015/06/15/game-over/).