Vaguely dark ages/Arthurian/Fairy Tale/Lyonesse-ian
Original OD&D LBB with Gygaxian OD&D Houserules & some Greyhawk ability score modifiers (STR to hit only; CON to HP; DEX to AC for Fighters only).
Humans, Elves & Dwarves for PC Races.
Clerics are either "Druids" or "Hermits" (vanilla OD&D Clerics with campaign appropriate names & flavor; not New Age/Wiccan/Nature worship Druids but Clerics that are called Druids because that's whay they call religious functionaries in Lyonesse).
Literal interpretation of OD&D class-based weapon and armor restrictions; Clerics cannot use magic edged weapons; Magic-Users cannot use magic armor or magic weapons aside from daggers (or Arnesian "magician swords").
Hit Points are rerolled at every level a la Empire of the Petal Throne; the higher of the old or new HP is retained.
Not tolkein/modern/WOW/Games Workshop/Scottish axemasters but gnomic crooked midget worms of the earth akin to Rumpelstilskin and Norse mythology.
Not Tolken/RPG/Metrosexual/New-age Elves, but Fairies from Fairyland without a consistant appearance. Low CHA Elves are grotesque, high CHA elves are elegant.
Between sessions Elves reside in Fairyland; at the beginning of every session Elf PCs leave Fairyland and enter the mortal world at which poin they choose to function as a Fighting-man or Magic-user for that session.
Explicitally stated: There is NO way a PC can use, benefit from, powergame or exploit the transition to and from Fairyland and the Mortal World; it is an arbitrary and irrational phenomenon. YOU KNOW BETTER when I'm DMing.
OD&D LBB spells along with spells from Elritch Weirdness and selected Arduin Spells.
A saving throw is allowed vs. a Sleep spell; all Fairys & Fairy creatures possess the Elven 90% resistance to Sleep spells (and immunity to Ghoul paralyzation).
The 3d6 roll for starting gold is recorded as "Social Class"; if a Fighting-Man has a Social Class of 11 or higher they are a Knight (a loser landless Knight if you have an 11 Social Class)
If your Social Class is 18 you are a Prince or Princess!
Don't expect in-game benefits or powergaming via Social Class
The PC with the highest Social Class is the Caller/Leader of the group; in case of a tie, the higher CHA score breaks it.
Armor & Weapons
STR and DEX weapon and armor prerequisites.
Use the AD&D weapon and armor price lists, but...
Leather and Chain armor only; Plate mail is very rare and very expensive, don't count on finding any.
No crossbows; two-handed swords are also very rare and very expensive.
All weapons inflict 1D6 damage w/o any STR modifiers but Greyhawk STR to hit modifiers for Fighting-Men.
Weapons use an amagamation of the Greyhawk and AD&D weapon vs. AC tables; this information is not provided to PCs. Roll the dice and I'll tell you if you hit. But...
A positive modifier on the Weapon vs. AC table is negated if your opponent is wielding a weapon that is longer than yours (Ex: The generous Dagger vs. Unarmored modifier is negated if your opponent is wielding a longer weapon).
"Beat The Wretches" houserule.