A couple of years ago, the Mircosoft developer 
network magazine offred a couple of suggestion for 
CD. (When you were on the developer network you 
received around 40-50 CD every couple of months)
I remember a few ones :
- You can put them under beer glasses
- Put several together with a string and you
  get a nice mobile to hang from the ceilling.
- Disposable freezby
...

Cheers,
Yann Stettler