This was an idea that I came up with in conjunction with a couple of other players (people playing a Wizard and Bard, natch) sometime last year. The ideas are a combination from all three of us, but the mechanics are nearly all mine. I have admittedly never used this ritual. It's not gotten any kind of playtesting. I'm not even sure it will be interesting for the majority of people who play D&D4e, but I thought it would be fun to (re)post anyway. First up is the ritual, then I'll post commentary on it after the mechanics and description.
Casting Time: 10 minutes
Duration: Special (see description)
Component Cost: 500gp
Market Price: 2500gp
Key Skill: Arcana (special)
Description: When activated, Phantasmal Harmony brings into being a full illusionary band of up to 5 people as well as appropriate lighting, sound, and and entertaining light show/fireworks display. The exact song and nature of the display is decided by the bard at the time of activation. This show provides morale bonuses for all allies within a close burst 5 radius with a duration determined by the Arcana check made at the time of casting. The exact nature of the bonuses is also determined at the time of casting. Although the bonuses last for a limited duration, the illusionary aspect lasts for up to 10 minutes or can be ended as a free action by the activating bard.
Casting the ritual for Phantasmal Harmony requires two people, a wizard and a bard. The average of their Arcana checks determines the duration of the morale bonuses as determined by the following chart:
19 or lower = 1 turn
20 to 29 = 2 turns
30 to 39 = 3 turns
40 or more = 4 turns.
On a natural 20 on the Arcana check by either the wizard or bard involved with the casting, the two rolls are instead added together to determine the result. At the time of casting, the nature of the morale bonuses is also decided. The bard may pick from any two of the following: +1 to all defenses, +1 to attack rolls, or +1 to saves.
Once the ritual has been cast, it is not activated immediately. Instead the ritual generates a small, tear-drop shaped piece of solid magic that, when thrown to the ground by the bard or wizard who participated in the ritual, will begin the effects. This item has no selling value and disappears if handled by someone other than the participating wizard or bard.
Commentary: So where do I begin to head off the criticism that I would expect? First, yes, it's a ritual that directly impacts combat. I don't remember seeing any of those in official sources (though I may be wrong) and I do realise that rituals generally are supposed to be more utilitarian magic. Combat magic is largely the domain of powers, not rituals. This is operating off pure Rule of Cool and not really the expected design parameters. The image in my mind is the bard or wizard activating this ritual, epic music ringing out with brilliant lights to inspire the PCs (or maybe demoralize the NPCs, depending on how you want to look at it. +1 to attack rolls can also be read as -1 to enemy defenses after all) for a few short, but important, rounds.
I expect that some people feel that there are too many bonuses and they're too large. At level 6 when the ritual can first be learned and cast, they are indeed hefty. But I deliberately avoided providing rules for scaling it up (it wouldn't be hard. At level 16, bonuses are +2, at level 26, bonuses are +3) so that as the characters advance in level, the ritual becomes less of a "must have" and more of a "nice to have" without ever completely being rendered useless. The save bonus becomes the best part of the ritual as a campaign progresses since it doesn't need to scale and that was again a deliberate design choice.
I feel the radius for the effect is solid. it's a wide radius, but not so big that allies couldn't find themselves out of it by chance, choice, or enemy actions. I also feel the duration is good. One of the balancing factors at lower levels is that, barring a crit, it would take an excellent roll from 2 characters to go more than 2 turns. Higher level characters will have an easier time getting more turns, but they're also getting less mechanical benefit per turn out of it except for the save bonus.
So there you go, Phantasmal Harmony. It's not a ritual for every game. Very serious games might find it inappropriate to the tone and setting. For the game that this ritual was developed for, there was a difference in opinion even from everybody involved. The DM pictured it as a more period/fantasy appropriate performance, while all the players who worked on it envisioned it more as a fantasy rock band event.
But it's ~fun~. That's why it was developed, that's why people should use it. I'm just picturing a bard's player saying "Okay, I'm using Phantasmal Memory" at the start of a fight and someonewith a mp3 player or laptop cueing up "Princes of the Universe" from Queen. Would that be awesome? I certainly think so.