Rules Hack - Ability Checks

At some time during the course of the game, a random roll will be required that's right outside the scope of the rulebook.  What if someone tries to haggle with the innkeeper?  What if a Hero is trying to climb to the roof without benefit of a Thiefly Ability (those are handled differently in my game as well, but one thing at a time).  This would be handled using Ability Checks.  Ability Checks are simply d20 rolls against an Ability, such as Strength, Wisdom, Constitution, etc.

Note: Apparently this is not new.  Swords & Wizardry has this, Castles & Crusades has it, 2nd Edition D&D had it (although in a sort of slapdash manner), and Tunnels & Trolls had it longer than any of those.  This, however, is my (hopefully) unique take on it.

As noted above, Ability Checks are used for many actions.  What makes them different in our rules hack is that they are also used for skills and saving throws.

I can hear the cries of "heresy!" and "3rd Edition!" now, but hear me out.

It simply makes sense to have Ability Checks used as Saving Throws.  It frees you from the tyranny of having to justify a Save vs. Dragon's Breath to avoid a lasso entangling you.  Now, instead of that, you can simply ask for a DEX Check.  And you can give certain character Classes and Races bonuses to specific situations (acting as Skills and Saving Throws) instead of making up a new procedure, or having to print yet another table.  A Dwarf and a Wizard might get bonuses to save vs. magical effects.  A Thief would get a bonus to any roll he made while attempting to steal something.  Very simple, very effective, doesn't require a hundred splatbooks.

Mechanics
Very simply, an Ability Check starts at 8 or less on a d20.  The Ability Score Adjustment adds to this (so a +4 would mean a 12 or less on a d20 for success).  Not only that, but as you rise in level, the Ability Checks increase.

Primary Checks
After the initial calculations, then you pick what you want to be your most rapidly advancing Ability Check.  For example, a Warrior might choose Strength.  This is called the Primary Check.  That Check will improve by +1 every two levels, plus add 2 to it in the beginning.  The rest will advance every 3 levels.  Checks follow this Table as you rise in level: 

Level	Primary Check	Other Checks
1	+2	+0
2	+3	+0
3	+3	+1
4	+4	+1
5	+4	+1
6	+5	+2
7	+5	+2
8	+6	+2
9	+6	+3
10	+7	+3
11	+7	+3
12	+8	+4
13	+8	+4
14	+9	+4
15	+9	+5
16	+10	+5
17	+10	+5
18	+11	+6
19	+11	+6
20	+12	+6

The various Classes and Races will give you bonuses on some specific applications of Ability Checks.  Some are codified in the text, others are unwritten.  Still others are determined on the fly.  Anytime everyone in the group agrees that a Hero should get a bonus on an Ability Check, he gets it.

Note: Since I run with Ability Score adjustments only (It's not STR 12, it's STR +1), you may have to adjust the base number higher, say an 11 or less to start, instead of an 8. 

Common Situations and Ability Checks
I'm just listing a few, though close to 40 examples appear in my game.

Fear (WIS) - Some creatures instill blind, unreasoning fear into a person, scaring him stiff (cannot move).  Roll to resist.

Leap (DEX) - Horizontal jump. 

Save vs. Paralysis (STR) - Some monsters and spells can paralyze or hold victims, immobilizing them through magical means. 

Save vs. Breath Weapon (DEX or CON) - It's just a bad idea to sit there and let some creature, like a dragon, breathe on you.  DEX is for dodging and diving for cover.  CON is when something like poison gas is being resisted.

Opposed Ability Checks
These are used when two people are rolling against an Ability, and they are competing against each other.  For example, you would use an Opposed Ability Check when two people are racing to the top of a cliff wall, or when one person is trying to grab another. 

Opposed Ability Checks are simple.  Both people roll d20, and the highest roll wins.  That means that if one person had a Check of 18, and rolled a 4, and the other person had a Check of 13, and rolled an 8, the person who rolled the 8 wins.  Obviously, anyone who rolls over the Check fails.   

Critical Success
If you roll precisely your Check, you get a Critical Success, and something special happens above and beyond the effect you were looking for.  So, if you had a Check of 13, and you rolled a 13, you got a Critical.  Critical Successes on Opposed Ability Checks mean that the person who gets the Critical wins, regardless of how high the other person rolled. 

And it's important to note that the Checks don't have an ever increasing difficulty, it's simply make that roll, or not.  There's no adding or subtracting any modifiers except in special circumstances.

Just an idea.  It's what I'm using in my game, at any rate.