(I probably ought to note here that I am not observing the variable casting times of certain editions of Dungeons & Dragons. In my campaigns, memorized spells are cast instantaneously, whereas ritually cast spells have a uniform casting time of one turn [ten minutes].)
Here, then, are my latest revised rules for ritual spellcasting...
Ritual Spellcasting Variant 3
The standard rules of normal spellcasting apply (verbal and/or somatic components only; casting time of 1 round; memorization of all spells in 1 hour after 8 hours of sleep), but spellcasters may also cast any currently unmemorized (or unprayed for) spell that they are qualified to cast (i.e. are of a high enough level to cast) with the following restrictions:
- Casting time is increased to 1 turn, after which the spellcaster makes a saving throw vs. magic. If failed, the caster loses 1 point of strength per level of the spell. Strength lost in this manner is fully recovered after 8 hours of sleep.
- The casting must be uninterrupted. If it is interrupted, the spell is disrupted, but the caster must still make a saving throw or lose strength as described above.
- Material components must be used. Magic-users may use either a magic circle with candles or incense, or an alchemical catalyst to be imbibed, poured, or otherwise destroyed. Clerics may use items appropriate to their religion and culture such as censors, holy water sprinklers, bells, chimes, gongs, prayer wheels, candles, bonfires, etc.
- For magic-users, the book containing the spell must be available to consult during the casting. For clerics, a holy symbol, holy book, or sacred object must be present.