I have a cd stuck in my external superdrive. How can I eject it?

Here is a list of some ways to eject a CD/DVD. You can try using the "drutil" command as mentioned here. You could try restarting the computer in case an app won't release control of the disc.

Of course if there is an actual problem with the drive's motor/eject mechanism or the slot/tray is damaged or blocked, then the above suggestions won't help and the drive will need to be taken apart to recover the disc.