Well, I hinted at it in the comments for the previous entry a moment ago, but I was on the path to becoming the Nerevarine, something I can actually spell properly now having seen that word so many times, when I started a quest that demanded three things from a local dungeon.  It turns out I had already looted it many months ago, which made me a bit nervous.  When I got there, I found the big shield was still there (because it was a heavy piece of junk), but when I looked for item three...  nothing. Not wanting to turn on the computer to ask a wiki, yet again, for some sort of idea what I could do to fix things, I searched other dungeons of a similar theme to see if THEY had such an item.  Nothing.
 
Today I checked the wiki, finding that there is just 1 of these items in the whole of the game. I think I looted it, I think I sold it, and I think I sold it to the one NPC in the game who irregularly purges his entire inventory.  In other words, I am screwed, and cannot complete the main quest at all. Despite having gotten further in the game than I have ever been, reputation 15, top of the Fighter's Guild (via bloody coup), nearing top of the Mage's Guild through grinding and finding trainers, buddy to Ashlander tribes and all-around badass, I cannot complete the game normally because I'm missing a stupid cup.
 
I write this after having, for the most part, a lot of very cool moments in the game, and a lot of surprises.  But I realize that the open-world feel is, finally, a ruse. May Skyrim be different.  I'm not as critical of the idea that one NPC will replace the other if you kill one now, since an equivalent problem, missing a proper quest item, is a huge bummer. If they fixed that in Oblivion so be it, but I've seen broken quests in that game too.  If it's supposed to be a simulation game, where you really can screw yourself, great, but they need to work on that angle a lot more then, because playing that game one can be under the impression that you can run around randomly AND complete the game's finicky missions, rather than choose between them.
 
I will play the game now to see if I can't find where I put the cup, since if I put it in one place where I've been stashing stuff, or sold it to a few of the few stores in various towns I dumped loot on, I can resurrect this game. Since I can't create the item (this is the XBox version), this is my only route. I may very well have lost the ability to finish the main quest.
 
Now I know how King Arthur felt: "Hey, Galahad!  Come back from heaven and give me the damned cup back, I need it for this stupid quest!"