Hi this is my first post so I hope I can do this correctly!
I teach elementary school kids at a Hagwan (I do have one class with middle school kids as well). I have found that getting the kids to remember vocabulary can sometimes be a chore. I usually end up playing games with them. Pictionary is great for this (ziplock plastic bag with the vocab in it) but I have also discovered that playing memory games works really well. This is a game I remember from when I was a kid - you have cards face down and you turn over two at a time trying to find two that match. What I have done is make it so the kids have to find the matching picture for the word, or visa versa. Some of these are quite difficult so you can leave them out for a lower class and add them for a higher class. There are also some sets that have a lot - I usually divide the class up and when one group is done they swap card sets.
There is a little prep that you have to do. I would suggest printing these out on cardboard. If you print them on normal paper you can see though and the kids cheat. You can glue them to cardboard but that is a lot of work. Then just cut them out!
The rules I use are as follows (you can use what-ever rules you want): go in turns, turn over two cards per turn, NO moving cards around - leave them where you found them, when you find a matching pair you keep the cards and have another turn. The winner is the one with the most matching pairs. (I use a sticker system so the winner gets a sticker).
I hope you like :)