One of my studio go-to’s for an easy, educational game for group classes is Team Rhythm Dictation.
The students are split into two teams and are given a set of individual rhythmic note cards to use. (Click here to download a free set of individual note cards to use in your studio.) The barlines are made from some scraps of black foam board.
I indicate what the time signature is and then play a two-measure rhythm pattern on the piano. The students are encouraged to tap and count along, then see if they can place the correct note cards to replicate the rhythm that I played. Typically, I will play the rhythm 3-4 times, but after several patterns, the students were catching on quickly and often getting the dictation after only one or two plays!