I’m generally not a big fan of getting adult students to do mimes, some seem to be very uncomfortable under that particular spotlight. However, I have found that this mime activity with smaller, ‘universal’ actions performed in small groups goes down well, and students nearly always end up having a good time with it.
Start off by performing a couple of mimes yourself. For example, juggling, playing chess, eating spaghetti. Elicit the present continuous questions and write them on the board. Along with the short answer form.
When you think the students are ready, put them in groups of three to five and give each group a set of mime cards placed face down on the table. Group members take it in turns to take the top card and mime the action given. The other students try to guess what the action is by asking present continuous questions.