Head Shoulders Knees and Toes
This classic kids song is not to be underestimated. Done correctly, it will be so fun that the entire class will be in peals of laughter. Sometimes simple is best.
I think everyone knows the song, but a quick look on youtube will refresh your memory. However you will not need a copy of the song in class, just singing the words is enough.
The first time go through it slowly with the students, getting everyone to do the actions.
Next decide on a pose/action and a sound effect with the class. It’s best if they come up with the action, but you may need to come up with one yourself. Make it wacky and funny. Even have the action go for an extended or irregular amount of time. Use your whole body.
Tell the class that one body part in the song is replaced with the action. Sing the whole new song with the class together.
Replace another body part with another funny action. Rinse and repeat.
Keep going until you have a completely nonsense song. Sing along with the whole class and have fun!