Greeting and Leave-Taking Expressions

I have a class to teach (beginner adults) Wednesday. I've scoured the internet over and over again and I can't seem to find any activities for greeting and leave-taking expressions. (Or even an activity on one that I can change to practice the other).

Does anyone know one? Even if it's not for adults - I can modify the concept and adjust it to fit this class. I am just completely stumped.

Thanks!