If you are looking for something Christmassy to do, have a listen to this beat box version of the Christmas Story;

http://www.youtube.com/watch?v=CyuzSzdpE38

For an instant Christmas Nativity rap, choose a well-known Christmas Carol and create a rap version. Add percussion, (vocal or instrumental), and movement or mime. Create instant costumes with crepe paper and sellotape…. You can take the idea as far as you like; it can be a five-minute filler or a whole lesson!