Chekov's Spell -- This spell has a two-fold effect. The first is to make the target item almost-unnoticeable to anyone not specifically looking for it. The second is that someone who has seen the item will remember it when they encounter a situation that would be perfectly solved by use of said item.
A good camping-place with something extra: a gallows with a hangman, reduced mostly to bones and a few rags. It marrily hovers in the wind. Any manipulation will make it fall apart. An excellent camping place, except for the midnight hours, when ghosts of those executed haunt here. Some wail for their crimes, some re-live their execution over and over, some want to have a talk, and still some others want to scare the Living for fun.