lol. Have fun with THAT!
A few suggestions...
Hokey Pokey is a classic.
She'll be Coming Around the Mountain. (They can act out the characters in each verse). The following video may be good to show them to give them some ideas of what to do. Some can act like the girl riding the horse, some can pretend to be the horses, some can just be the random crazy dancing characters that stand around. They can switch roles. Watch the video, and discuss the different roles, and demonstrate how each of the could be acted out BEFORE the students try it. Try to get them to at least say the words like (yeehaw!). They will love it! lol.
It's a Small World After All. (Act out the words).
Row Row Row Your Boat- Act like they are canoeing around the room.
Everybody Dance- Youtube video by The Wiggles. (I hope you have access to tech for this!)
You can also just pick a good funky tune with a good beat, and take them through almost the equivalent of an exercise warm up- leg raises, jumps, squats, hops on 1 or 2 feet, jumping jacks, heel raises, whatever... Do different motion every 15-20 seconds or so (or every 8 or 16 bars if you understand that). In older grades, once they are comfortable, ask the students if any of them one to come up and lead the class in one motion. That makes them practice being the leader also. Do movements that are simples enough that the children realize that they can pick one out also. I would have them come up for 15 seconds or so, then pick another student who wants to come up and lead a motion. (Have an agreed upon motion during the transitions- such as clapping the beat, or doing heel raises to the beat.)
You can also just tell them to each pick an animal and act how the animal would act while listening to the music... Pick your favorite few motions, and have the students tell the class what they are doing, and show them. Then have the class mimic them the next time around.
You can also do something that is more slow and meditative. Pick a relaxing song and do slow stretches, and have the students mirror you. Mirror = If you go to your right with both hands, they go to their left with both hands.
You can play one slow song, and one up beat song...
One thing to note- It is VERY important to front load this activity by having them know that they need to LISTEN to the music, WATCH the teacher for cues, and have fun while also doing those two things. Screaming over top of the music means it is not dancing because they are not listening to the music. If not, mayhem will ensue- and still might if it is the first time you are doing it! I would have one dance move that is a frozen pose with my fingers over my lips while lightly doing a foot tap or something like that when you notice that things are getting noisy. That will bring them back. At that age, with their motor skills, the movements will need to be pretty simple for them to feel successful. If you just tell them to make up a dance, they are going to struggle. You will have to demonstrate and lead them through the activity. Since they are so young, pretty easy motions will be a challenge, and they will have a blast!
Make sure you stretch so you don't pull your back out of place or something! lol. That can be in the first meditative song... Afterwards, ask the students what they learned. Maybe you can pick out 4 motions- jump, sway, wiggle, turn- and do each one in a certain part of the song. In that case, have the students do each motion before you start the music (this way they can practice doing it, saying the corresponding word, and being quiet while doing so). (such as first verse, jump,/ first chorus, sway,/ second verse, wiggle,/ second chorus, turn. They can learn four English words that way.
Older students (for modification to other age groups) can be assessed to a greater degree. They can learn concepts AND English terms;
*Following another dancer's moves by mirroring (Mirror as a verb instead of a noun) You can explain the difference.
*Leading other dancers (Leader/follower)
*Learning that you can move to the music (beat/tempo/or pulse)
*There are slow motions, and there are fast motions (slow/fast)
*There are different styles of music (rock/pop/Kpop(lol)/jazz/blues/funk/reggae, etc).
*Different motions are appropriate for different moods in songs (mood/emotion)
*There are motions that are done in place, or motions that are moving (locomotor or non locomotor)
*There are different ways to move (sideways, forwards, backwards, zig zagging, etc
This should give you plenty of ideas. 15 minutes will get you through PART of one of these activities after you introduce the song (by video or singing yourself), then demonstrating motions, the word to describe the motions, then leading the class through the activity. DONE! Bam. Next class. You will be amazed how good you have it down by the fourth one!