Over on digg yesterday, I came across a story about a Zelda bug. The person who encountered it, created a couple Youtube videos of it.
*WARNING POSSIBLE SPOILERS AHEAD*
Part 1:
Part 2:
This bug emerges when one saves the game at a certain time and attempts to resume from that point.
In the basement of the Sanctuary in Kakariko Village, after moving the statue with the Dominion Rod, you'll enter this cave with a giant, dilapidated cannon inside it. You will be accompanied by Shad. Once you approach the cannon, Medina will giggle and suggest you warp it to a location where you can use it, but will not do so as Shad is in the cave (Medina doesn't like warping or transforming Link in front of others). What you should do then is talk to Shad a couple times to get him to leave. If you do not, you cannot warp the cannon, transform, or even leave the place.
If one were to save at this moment and quit the game, upon resuming, the game starts you back in the cave but fails to load Shad with it. Medina treats the situation as if he's still there. Shad even stops you with a short cinematic by asking you where you are going if you try to exit. You're trapped. Committing suicide only starts you back at the cave's entrance. Unless Nintendo patches this, the only solution now is to erase your game save and start over from the beginning. This point in the game is roughly 35-40 hours in (for me, it was more as I have taken more time to explore).
The solution, obviously is to NOT save at this point. I recreated this bug myself, so I know it exists (don't worry, I staggered my saving of the game between the three slots). To prove this bug, I made two different save points. One before shewing away Shad and one after. Resuming the game without dismissing Shad caused the bug to emerge (Shad was not there to talk to, but the game thought he was still there). The save I resumed after I talked to Shad twice to get him to leave worked fine. I could then exit from the entrance, warp the cannon to a different location, and have Medina transform myself. I suggest you go ahead and have Medina warp the cannon to it's proper location (if you want to know where that location is, consult a guide or FAQ, I'm just giving enough information to prevent others from falling victim to this bug). Once you find the proper location, you are safe to save your progress.
One preventative measure from this and other undiscovered, potential bugs is to not continually overwrite the same save slot, but to stagger your saves. By this I mean, the first time you save to slot 1, the second time you save to slot 2, the third time to slot 3, the forth time to slot 1 again, and so on. If you were to accidentally encounter this bug (or a bug that has yet to be discovered), you won't have to start at the very beginning--ensuring your sanity.
I hope this helps! I know if I was in the shoes of the person who came across this bug, I'd be devastated by having to repeat 35-40 hours of game play. However, despite this flaw, the game is awesome folks. ...just keep your eyes open for it.