From the Book of Wonderous Inventions (1987, TSR), with this portion by David Ladyman of Austin, Texas. I've tried to organize this text by groupings, but know that a lot of this is verbatim of the text.
Moodarvian Rings of Emotion
It's a ring which casts an illusion affecting one or more of the five senses, drawing from the emotions and intents of its user.
Typically they come in one of five types: 1) appearance, 2) smell, 3) taste, 4) sound, or 5) touch. See below for examples of each.
For each, there are three sub-types: A) Attuned to a person, B) attunded to a group of people, or C) set for a fixed image.
Sub-Type A: When attuned to a person, the the illusion is altered by changes in that person’s emotions and thoughts.
Sub-Type B: When attuned to a group of people, the illusion is influenced by the melange of emotions of all within its range.
Sub-Type C:When set for a fixed image, the Ring projects that illusion at all times.
Sight:
Personal - Enhances its owner’s presence, making plain girls pretty, shy men valiant, and timorous men courageous. With practice, one can use it to disguise appearance when one wishes to pass unrecognized.
Group - Rings of sight cloak the setting in ageeably soft beiges.
Fixed - When mounted in a non-descript room, a ring of sight can transform it into a scholarly study, a rosy boudoir, or an elegant salon. Of course, furnishings must roughly conform to the image presented for any lengthy effect, and a ring of touch might be added to harmonize the impressions of any who come into the room.
Smell:
Personal - Acts as a deodorant, radiating the most expensive of sachets or colognes. It can clear the air of clinging odors or foul the nearby atmosphere to the point that no one would want to approach its wearer. A ring of smell can impart a pine-fresh fragrance, a stimulating seabreeze, or other refreshing aromas dependent on the mood and impulse of its owner.
Group - Induces slightly sweet but unidentifiable odors.
Fixed - Mounted in rooms such as a privy, where a ring of smell can overcome the strongest of disagreeable odors with rosewater freshness.
Taste:
Personal - A shortcut to elegant dining. By imagining the dish desired, the most extravagant banquet can he served, if the chef is sufficiently skilled with the illusions his ring can devise. Woe betide, though, if the chef is upset or depressed, for these emotions will work their way into his creations as well.
Group - When used in public restaurants and taverns, mask the food with bland flavor.
Fixed - A ring of taste, when one hasn’t the skill to evoke savory detail in each dish sufficient to fool a gourmet, can be mounted in the dining room to add an overall flavor to each meal, called forth by its owner. It can serve to make bland food tasty, but one has heard of infamous dinners in which each course was even more garlic filled than the last, or so bitter that guests had to pry open their puckered lips with forks to voice their thanks for the meal and regrets for an early departure. Such disasters are usually due to an undiscriminating palate or taste buds temporarily warped by a head cold or other slight illness.
Sound:
Personal – Provides its wearer with his own individual theme music and sound effects. A rousing theme for adventuring, passionate strains for courtship, and martial chords for combat are all within this ring’s capacity. Care must be taken that it does not control its wearer in a tense situation, however: a fearful flourish has served to rout more than one panicky wearer, unaware that he had provoked the very tremolo that spooked him.
Group - Provides harmonious and inoffensive background music
Fixed - Background music is a useful addition to any social occasion, and such Mood Rings are more versatile and prompt than most orchestras. They certainly require less upkeep. This has not escaped the notice of professional musicians, and musical groups from all over have been among the most vociferous in their opposition to Mood Rings. In scattered cases, musicians have struck back, lurking nearby and producing discordant music calculated to jar the tinniest of ears when combined with a Ring’s music. Some fixed rings of sound have proven maddening for all in range, particularly the wearer. After hearing the same tune repeatedly, without pause, for days in a row, most early users developed severe mental aberrations. The experiment is seldom repeated.
Touch:
Personal - A personal ring of touch, although less generally useful than its brothers, can render the coarsest complexion satin-soft and subdue the roughest hemp into velvety smoothness.
Group – Cloak the setting in agreeable soft textures.
Fixed – Makes uncomfortable or utilitarian furnishings into comfortable rooms.
Notes: These rings are also popular in children's playrooms, although only the wealthy can afford them. Children's imaginations, when reinforced by rings, can take them anywhere, soaring above the clouds, battling to save a kingdom, or adventuring in the depths of the earth. Strong-willed guardians should always be present, lest children literally scare themselves to death.
Hazards: Perils occur when Mood Rings come under the control of inexperienced or unaware users. Just as Rings provide positive feedback to positive emotions, anger, distrust, nervousness, and especially fear, are reinforced by rings in a vicious circle of escalating images. In particular, it was soon found that rings mounted to enhance social gatherings also provide thieves and other intruders with those images they fear most, beginning with flickering shadows in the corners, the hint of a dragon's sulfurous breath, the sting of hidden traps, and the tread of approaching footsteps. The most imaginative fall prey to other-worldly guardians and worse, terrors that previously existed only in their darkest nightmares. Further, rings attuned to individuals or groups there is a risk of a strong negative emotion overriding the generally positive flow. When this happens, blackened walls, prickly seats, discordant caterwauling, and the stench of rotting eggs predominate. Wise owners make sure that such rings are easily removable when circumstances demand it.
