I generally stick to 1E rules, but I normally have the following modifications when I run a game (I'll constantly update this list as the game goes on):
->I use a silver scale instead of the normal gp scale. 1 gp = 20 sp = 400 copper pennies = 400 iron rings/drabs. Experience is awarded per sp, so this doesn't really alter anything.
->Being 10th century-ish, longswords are the weapons of high status fighters and chain mail is uncommon. A fighter wearing chain will draw attention and need to prove he is of veteran (or high) status.
->Initiative uses d10, with low roll winning initiative and indicating the group's action segment.
->Surprise gives one free segment for spell casting purposes and one free round for melee purposes.
->Characters may heal another character for 1 HP after a fight.
->Being reduced to 0 HP indicates that the character is knocked unconscious. If a character goes below 0 HP, he/she will bleed out at the rate of 1 HP per round unless tended to. Each HP below 0 indicates the number of days of unconsious bedrest the player must spend in recovery.
->To level up, characters must be trained by an NPC of at least 1 level higher than the desired level and for a number of weeks equal to the new level (except for MUs, which require 1 month per level).
->Specific to Rangers: a standard +1 to hit humanoids/giants, with no other hit/dam bonuses; starting base of 75% chance to track, rather than 90%; surprise benefits only in unpopulated, outdoor regions; can be any non-evil alignment; can use the following weapons in combat, allowing 2 attacks per round at any level (but with -1 to hit with the primary hand, -2 to hit with the secondary hand): longsword/shortsword + dagger; handaxe + dagger; club + dagger; dagger + dagger; handaxe + club; shortsword + club.
->Clubs do 1-4 damage versus S/M targets, not the normal 1-6 damage.
->Magic Items can be identified at any time.
->Spellbooks are simply compilations of scrolls, and a MU could cast directly from the book (destroying the spell and potentially damaging nearby spells).
->MUs of any level may write a scroll/put a spell into a spellbook, provided they acquire the necessary ingrediants and spend the appropriate time.
->MUs can research new spells after harvesting relevant components and spending massive amounts of money and time. Players would write up the new, unique spell and submit it for DM editing. Each time they research a spell they have a [(10% x level) + (INT score)%] chance of success. A new, successful spell has been researched each time a character levels up.
->Spellcasters must sleep 6 hours to retrieve level 1-9 spells, with an additional 30 minutes of study/meditation per spell to be recovered. 0-level cantrips and orisons require 4 hours of sleep and 15 minutes of study/meditation per spell recovered.
->In addition to magic users' Unearthed Arcana 0-level cantrips and orisons, spellcasters can use some cantrips and orisons from 3E (the PHB and UA 1-level spells that meet these descriptions...light, detect magic, message, etc are considered 0-level cantrips in this game):
0-LEVEL CLERIC SPELLS (ORISONS):
Create Water: Same as 1E 1st level cleric spell.
Cure Minor Wounds: Cures 1 point of damage.
Detect Poison: Detects poison in one creature or object.
Guidance: Subject gains +1 on one attack roll.
Inflict Minor Wounds: Touch attack, 1 point of damage.
Light: Object shines like a torch.
Mending: Same as 1e 1st level spell.
Purify Food and Drink: Same as 1E 1st level cleric spell, but at 1 cu. ft./level.
Resistance: Subject gains +1 on one saving throw.
Virtue: Subject gains 1 temporary hp.
Cure Minor Wounds
This spell functions like cure light wounds, except that it cures only 1 point
of damage.
Detect Poison
Components: V, S
Casting Time: 1 round
Range: Close (25 ft. + 5 ft./2 levels)
Target or Area: One creature, one object, or a 5-ft. cube
Duration: Instantaneous
You determine whether a creature, object, or area has been poisoned or is poisonous. The spell can penetrate barriers, but 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt blocks it.
Guidance
This spell acts as a bless spell, but lasts only for one attack during a subsequent round.
Inflict Minor Wound
This spell functions like cause light wounds, except that it causes only 1 point
of damage.
Light
Components: V, M/DF
Casting Time: 1 round
Range: Touch
Target: Object touched
Duration: 10 min.
This spell causes an object to glow like a torch, shedding bright light in a
20-foot radius (and dim light for an additional 20 feet) from the point you
touch. The effect is immobile, but it can be cast on a movable object. Light
taken into an area of magical darkness does not function. A light spell
(one with the light descriptor) counters and dispels a darkness spell (one with
the darkness descriptor) of an equal or lower level. Arcane Material
Component: A firefly or a piece of phosphorescent moss.
Resistance
This spell acts like a bless spell (with regard to saving throws), but only works for the subsequent round, against one event.
Virtue
Components: V, S
Casting Time: 1 round
Range: Touch
Target: Creature touched
Duration: 1 min.
The subject gains 1 temporary hit point.
0-LEVEL DRUID SPELLS (ORISONS):
Create Water: Same as 1E 1st level cleric spell.
Cure Minor Wounds: Same as cleric orison.
Detect Balance: Same as 1E 1st level druid spell.
Detect Magic: Same as 1E 1st level cleric spell.
Detect Poison: Same as cleric orison.
Flare: Same as 1E MU cantrip Firefinger.
Know Direction: You discern north.
Light: Same as Cleric orison.
Mending: Same as 1E 1st level MU spell.
Purify Food and Drink: Same as cleric orison.
Virtue: Same as cleric orison.
Know Direction
Components: V, S
Casting Time: 1 standard action
Range: Personal
Target: You
Duration: Instantaneous
You instantly know the direction of north from your current position. The
spell is effective in any environment in which “north” exists, but it may not
work in extraplanar settings. Your knowledge of north is correct at the
moment of casting, but you can get lost again within moments if you don’t
find some external reference point to help you keep track of direction.
0-LEVEL WIZARD SPELLS (CANTRIPS):
In addition to all the "useful," "reversed," and "personal" cantrips from UA (and the MU knows from apprenticeship), the following spells count as MU cantrips...
Acid Splash: Orb deals 1d2 acid damage.
Affect Normal Fires: Same as 1E 1st level spell.
*Arcane Mark: Inscribes a personal rune (visible or invisible).
*Detect Magic: Same as 1E 1st level spell.
*Erase: Same as 1E 1st level spell.
Light: Same as cleric orison.
Ghost Sound: Figment sounds.
Mage Hand: 1-pound telekinesis/level.
Melt: Same as 1E 1st level spell, except damage to cold creatures is 2 max.
*Mending: Same as 1E 1st level spell.
Message: Same as 1E 1st level spell.
Open/Close: Opens or closes small or light things.
Ray of Frost: Ray deals 1d2 cold damage.
*Read Magic: Same as 1E 1st level spell.
Ventriloquism: Same as 1E 1st level spell.
*Indicates a cantrip the MU knows from apprenticeship.
Acid Splash
Components: V, S
Casting Time: 1 segment
Range: Close (25 ft. + 5 ft./2 levels)
Effect: One missile of acid
Duration: Instantaneous
Saving Throw: None
Spell Resistance: No
You fire a small orb of acid at the target. You must succeed on a ranged touch
attack to hit your target. The orb deals 1-2 points of acid damage.
Arcane Mark
Components: V, S
Casting Time: 1 round
Range: 0 ft.
Effect: One personal rune or mark, all of which must fit
within 1 sq. ft.
Duration: Permanent
This spell allows you to inscribe your personal rune or mark, which can
consist of no more than six characters. The writing can be visible or invisible.
An arcane mark spell enables you to etch the rune upon any substance
without harm to the material upon which it is placed. If an invisible mark is
made, a detect magic spell causes it to glow and be visible, though not
necessarily understandable. See invisibility, true seeing, a gem of seeing, or a
robe of eyes likewise allows the user to see an invisible arcane mark. A
read magic spell reveals the words, if any. The mark cannot be dispelled, but
it can be removed by the caster or by an erase spell. If an arcane mark is
placed on a living being, normal wear gradually causes the effect to fade in
about a month. Arcane mark must be cast on an object prior to casting
instant summons on the same object (see that spell description for details).
Ghost Sound
Components: V, S, M
Casting Time: 1 segment
Range: Close (25 ft. + 5 ft./2 levels)
Effect: Illusory sounds
Duration: 1 round/level (D)
Saving Throw: Will disbelief (if interacted with)
Spell Resistance: No
Ghost sound allows you to create a volume of sound that rises, recedes,
approaches, or remains at a fixed place. You choose what type of sound
ghost sound creates when casting it and cannot thereafter change the sound’s
basic character.The volume of sound created depends on your level. You can
produce as much noise as four normal humans per caster level (maximum
twenty humans). Thus, talking, singing, shouting, walking, marching, or
running sounds can be created. The noise a ghost sound spell produces can
be virtually any type of sound within the volume limit. A horde of rats
running and squeaking is about the same volume as eight humans running
and shouting. A roaring lion is equal to the noise from sixteen humans,
while a roaring dire tiger is equal to the noise from twenty humans.
Ghost sound can enhance the effectiveness of a silent image spell.
Ghost sound can be made permanent with a permanency spell.
Material Component: A bit of wool or a small lump of wax.
Mage Hand
Components: V, S
Casting Time: 1 segment
Range: Close (25 ft. + 5 ft./2 levels)
Target: One nonmagical, unattended object weighing up to 1 lb per level of caster.
Duration: Concentration
You point your finger at an object and can lift it and move it at will from
a distance. As a move action, you can propel the object as far as 15 feet in
any direction, though the spell ends if the distance between you and the
object ever exceeds the spell’s range.
Open/Close
Components: V, S, F
Casting Time: 1 segment
Range: Close (25 ft. + 5 ft./2 levels)
Target: Object weighing up to 30 lb. or portal that can be
opened or closed
Duration: Instantaneous
You can open or close (your choice) a door, chest, box, window, bag, pouch,
bottle, barrel, or other container. If anything resists this activity (such as a bar
on a door or a lock on a chest), the spell fails. In addition, the spell can only
open and close things weighing 30 pounds or less. Thus, doors, chests, and
similar objects sized for enormous creatures may be beyond this spell’s ability
to affect.
Material Component: A brass key.
Ray of Frost
Components: V, S
Casting Time: 1 segment
Range: Close (25 ft. + 5 ft./2 levels)
Effect: Ray
Duration: Instantaneous
Saving Throw: None
Spell Resistance: Yes
A ray of freezing air and ice projects from your pointing finger. You must
succeed on a ranged touch attack with the ray to deal damage to a target. The
ray deals 1-2 points of cold damage.
