I have had so much fun with this FREE app called Jam. The app requires you to sing lyrics into the ipad and then Jam makes your voice sound half reasonable and then adds background music. It only gives you once choice of music genre for free, you need to pay for the others.
1, Children could read a story and then write a song for the retell.
2. The students could make up a class theme song.
3. The students could write a song about historical events and then record their song.
4. The students could make a song using their times tables.
Really the opportunities are endless.