I'm not sure where I first learned about this, but my students LOVE it, and it is a great filler for those extra 2 minutes, or a good attention getter!!!
I've found that this works best with students over 2nd grade level, and will hold the attention of even a room full of adults!
I begin by asking students to let me tap for 4 beats, and then ask them to do the same thing as an echo counting 1234 as I, then they tap. (I might tap my fingertips together.) I then warn them that I am going to change where I tap every 4 beats. It ends up that they are echoing my tapping so that they are 1 move behind me. It works out perfectly with lots of smiles!
When they get really good, do something different than the tapping, like stomp a foot, or wink an eye. Children love to be in the "hot seat", so I have a student volunteer to lead the group. This is so good for the leader to switch to a new move every 4 beats (improvising), and it's a great way to assess steady beats for the rest of them. The students are to count out loud, or whisper 1234, and they change on each 1. (may want to add a 1+2+3+4+ so they don't speed up!) Sometimes, I will play a song they LOVE and have them do their round that way! (World Playground's Bongo Bong is their all-time favorite!!!) Enjoy!