Glue four of them together and use the last one on the back. You can also bind them using the holes at the bottom of each disk (where you can see the locker symbol).
If you don't like the old labels you can make new ones and decorate them as you prefer. We choose a "Calvin and Hobbes" strip, so our pen-holder is not only recycled but it also tells a short story!
p.s. Did you like this project? Click here for another activity that involves recycled floppy disks.