You may have come across The Mirror Game, which begins with the teacher doing an action and saying out loud what they are doing, then the whole class copy – for example:

Teacher: I am touching my nose! (touches nose)
Children: I am touching my nose! (all touch their noses)
Teacher: I am spinning around! (spins around)
Children: I am spinning around! (all spin around)

Next, the children play in pairs, taking turns to lead (it helps to model this first with another adult).

This is great fun for young children and helps to get them talking.

I like to extend this game to help build vocabulary; here are just a few examples:

Play with target verbs. (“I am rotating my thumb.”)
Play with target nouns. (“I am scratching my shin.”)
Include conjunctions such as so and because. (“I am standing on tiptoes so I can see over the shelves.”)