I think a repository site for 4e House Rules is an awesome thing, and I have no doubt it will be done elsewhere. EN World has a forum for it, but forums are terrible for this sort of thing, especially on a site that lacks search functionality (unless you're a paid member).
You don't have to limit yourself to house rules you create, this is a repository. One thing I'd like to make sure of, though, is that everyone is diligent about crediting the authors of House Rules they pick up from other places on the web. If you credit someone for their idea and then link them back to this page, we'll get even more publicity and editors out of the deal!
There are numerous examples in fantasy literature and media of using mundane items to store ritual magic, which can be unleashed at a later date. These rules attempt to emulate that for 4th Edition D&D.
Thanks to Klaus and Freedom Canadian over at Circvs Maximvs for helping develop this idea.
Note: I know that the rules allow you to write ritual scrolls, but they still take half the normal time to cast…anywhere from five minutes to four hours.
Storing a Ritual
Storing a ritual works the same as performing a ritual (PHB 298), including the ability for others to assist. It requires the same components and takes the same amount of time. At the end of the ritual, however, the ritual caster must expend a healing surge in order to lock the ritual into an item related to the ritual itself, known as a ritual object (a key for Knock, a desiccated tongue for Comprehend Languages, etc.).
A ritual will remain stored in the object for a number of days equal to the character’s Intelligence modifier (min. 1).
If a character has a stored ritual when he takes an extended rest, he recovers one fewer healing surge per stored ritual. For example, a wizard that normally had eight healing surges after each extended rest would only start with seven if he had stored a Detect Secret Doors ritual the previous day but had not used it yet.
A character can store a number of rituals equal to his Intelligence modifier (min. 1).
Using a Stored Ritual
It requires a standard action and the expenditure of another healing surge to use a stored ritual. The character must be holding the ritual object when he takes the action.
Releasing a Stored Ritual
A character can release a stored ritual at any time as a free action. He need not be holding the ritual object, and the ritual magic dissipates without effect. He does not immediately regain his healing surge, but can recover it with an extended rest or other ability that allows the recovery of a healing surge.
Optional Rule: Prior Knowledge
In order to store a ritual in an object, the ritual caster must have knowledge of the specific circumstance in which he will use the ritual.
So, he could store a Knock spell to the evil duke’s chambers, but only because he heard a rumor that it was magically locked and was able to interrogate a retired castle guard about what the door looked like. If he had not done the investigation, he wouldn’t have known enough to store the ritual for that door.
Or, he found out that the last three adventurers to delve into the Caves of Chaos all came back with the dread Burning Plague, so he could store a Cure Disease ritual in a piece of fruit that would help protect his comrades when they attempt the delve the following day.
Halflings have same speed as dwarves, not humans. (source: Zander at EN World)
A repository of revised earlier-edition weapons, converted to 4e!