How do I manually eject a stuck disk from my Mac's SuperDrive?

I have a disk in my superdrive that won't eject. The disk played as expected but won't eject by any usual means. I've tried control eject, dragging to trash and unplugging/replugging but nothing works. The disk disappears then reappears. Any suggestions?

[Re-Titled by Moderator]

Original Title: SuperDrive not ejecting disk