Magical Item: Memory Saver
The memory saver is usually a crystal or glass ball, cylinder or cube. It's enchanted with a memory holding spell, which allows the user to implant one memory within. This memory can then be viewed at leisure as a hologram of sorts, complete with colors, smells, and sounds. The best memories are the strong ones, ones you can still recall vividly without the aid of a memory saver. Often they are used as a tool for legal proceedings; a person might have been robbed and they can remember the robbery, so it's recorded in a memory saver in order to assist with the capture and/or prosecution of the robber. Other times, a person might want to share their fondest memory with someone; the memory saver is good for that too.
Memories contained within memory savers do not fade or become blurry with time. The spell is woven into the crystal or glass object in such a way that it's infinitely self-renewing, so all you have to do is store the memory once. As people's memories can fade, this can be a good way to ensure that you can always remember another person or event. A memory can be stored regardless of how long it's been since the actual event happened. It could have been an hour or a hundred years; as long as you remember it, you can store it in a memory saver.
Some specialized artists have made memory savers that can store several memories, but they are large and fragile, best left somewhere where they won't be accidentally dropped. These are often used at funerals, to record and then play back memories of the deceased's life. Some people will record their own experiences on their deathbed, so that their loved ones can experience their life through their own eyes.
It is currently unknown why only a few shapes are capable of being given this particular enchantment, but experimentation is ongoing to find out. Spheres, cylinders and cubes seem to be the only viable shapes at the current time, but researchers hope that one day they'll figure out how to make the spell work with various other shapes, so that you can pick a shape you associate with the memory you plan to record, making it that much more special.