Not a gift card, but I got a day at a spa, put it in my desk drawer at work, and promptly forgot about it. I'm pretty sure I wouldn't be able to redeem it now although I haven't tried.
Hey, wait, why didn't you say anything before? If I had known it was that easy . . . okay, okay, okay, as soon as you start tearing up the restraining order, I'll start shelling out the moolah.