The gimmick: Another William Castle production, though this one quite a bit less tingling. For his 1960 film 13 Ghosts, Castle issued ticket holders a pair of glasses, the only way to see the ghosts on screen.
The result: This was one of the few Castle gimmicks that can still be replicated today. Modern DVDs of the film still include the special glasses, though the effect is said to be underwhelming.