New to the boards, looking at the different ideas. Didn't read every post in this thread, but it seems like you've created some fun items.
I had a different thought when I first saw the thread, here's my variation on the idea, inspired by stories:
There is some kind of trigger for a cursed item, perhaps the generic curse card mentioned early on, or other events determined by location cards.
When you get a cursed item card, instead of having a deck of special items, you get the next item in the deck you drew from. By the way, there's no reason to limit this to unique items, it could be common items or spells as well.
After you obtain your item, you then draw from the Cursed Item Story deck. Don't turn it over, it's a surprise.
You then have to decide before you actually use the item whether you want to chance the curse. You don't know the result, so it's pretty interesting story-wise.
Some curses should be harmless or almost harmless (lose the item, negate it's effect once, etc.) Others should be neutral, but have potential serious consequences (switch locations with the previous player, give the next player 5 clues [which could be a big help, or could trigger a story card), some could be more serious (lose 3 stamina or sanity, lose all items), and some could be horrible (the AO awakens, etc).
Bottom line - this is more realistic. If something is cursed, in many stories you don't know it. Well, that can't be done in this game, but at least you can make it a gamble to use. It also makes the curse system more flexible - imagine if you had a cursed elder sign, using it sealed the gate, maybe winning the game, but ended up killing all the characters.
