This may be more extensive than you're willing to go, but...
If you follow [guide|3454|this guide], you can remove the optical drive. From there, you can manipulate the white plastic sliders on the metallic side of the drive to slide the disc out. Alternatively, one the drive is removed, you have your choice of removing the screws on the metallic side of the drive, lifting up the casing, and pulling out the disc.
I've also heard of people inserting another disc with double-sided tape on it into the slot and fishing the drive out, but I can't comment on whether this works or not.
Good luck!