Picture Kim's game
You need an image, that is not too easy to remember (depending on the age and abilities of your participants). Different objects or people, of different color in different positions should be present on the picture.
The trainer first explains the game and the presents the image to the group.
The participants now have some (short) time to look at the image and remember as much as possible from it. A few minutes will be enough for that. Then, the image is removed and hidden.
Either immediately after that, or a few minutes later, the team has to recall as many details of the image as possible. What objects were shown in the image? What color did they have?