There are dozens of files on my computer regarding these types of things, to rules ideas, skirmish game designs, adventure notes and general random thoughts on gaming. I've found entire unfinished articles, long detailed world histories and brief character designs, some of which mean nothing to me now but were no doubt incredibly important when I wrote them.
This is both a great thing and a bad thing; great because I've got loads of material I can look back on and mine for ideas, bad because most of it I can't even remotely remember why I wrote the stuff and how it was going to be used. It was obviously important at the time, but not so important that I remember the details five, ten or even twenty years down the line.
Below is an example - I'm sure that I wrote this small D&D conversion to use the red box basic D&D material with elements of the D&D 3rd Edition design. I remember that at one point that I wanted to capture what I loved about old D&D and use the modules but do away with THAC0 and some of the elements of Saving Throws, as well as simplify the experience method. The terrible thing is that not only do I not remember writing this, but I'm even doubting that I wrote it at all, and that these notes are someone else's work that somehow ended up on my computer. However, I do remember creating the character sheet.
If this is of any use to you then go ahead and use it, although there are plenty of OD&D and OSR games that do this already. I have not corrected any abbreviations or errors and this is how it was on my computer.
WHAT YOU WILL NEED FOR THIS GAME:
Basic, red box D&D was the basis for this game, but any old OSR along those lines will do. Bear in mind that the attack rolls do not use THAC0 but the roll target number of 10+AC from 3rd Edition onwards.
You can use the standard 3D6 roll for each attribute, or you can roll 4D6 and discard the lowest number. Add up the remaining three numbers and that is the score you can put in an attribute. Do this six times, once for each attribute. You can then decide which attribute receives which score based on the kind of role you want to play.
Attribute bonuses apply using the following chart:
Attribute Score / Adjustment
3 / -3
4-5 / -2
6-8 / -1
9-12 / 0
13-15 / +1
16-17 / +2
18 / +3
Roll 1D8 for hit points, or 1D4 + 4 if you want better odds.
STRENGTH – bonus to CQ to-hit and damage rolls
INTELLIGENCE – for each +1, choose an extra skill
WISDOM – bonus to WILL saving throw
DEXTERITY – bonus to Rng to-hit score, bonus to REFLEX saving throw
CONSTITUTION – bonus to hit point score, bonus to FORTITUDE saving throw
The saving throws 'Fortitude', 'Reflex' and 'Will' are scored at 10 plus the applicable attribute bonus. Fortitude uses the Constitution bonus, Reflex the Dexterity bonus, Will the Wisdom bonus. A successful saving throw is a D20, scoring less than the saving throw score.
Attack rolls are D20 plus the relevant Attack Bonus. Rolling high, the initial target number is 10 or the target’s Reflex saving throw for a successful hit. This is modified by armour, raising the target number, making it more difficult to hit.
The STRENGTH adjustment score modifies hand-to-hand to-hit and damage rolls.
The DEXTERITY adjustment score modifies ranged to-hit scores.
Armour class is based on normal armour in the book but reversed:
Shield: +1 AC
Each player is given three points. They can use a single point to raise an 'Attack Type', this being either Ranged (Rng) for pistols and thrown weapons or Close Quarters (CQ) for fists and hand weapons. Each point spent gives a +1 bonus to their attack roll.
Characters start at level 0 and they must complete the same number of adventures for the level they want to attain. So, when they complete one adventure they go to level one. When they complete two more adventures they go to level two, when they complete three more adventures they go to level three and so on. (or, you can use the experience point system as normal).
For every level the character attains they get another single point to do ONE of the following:
Spend on either one of the attack bonuses
Roll another 1D8 for more hit points.
Add one point to a saving throw score (every 5 levels)