Surprise And Flash Maneuvers

All of these maneuvers, and the many possibilities they provide for characters to customize their fighting styles should give you the idea that the DM should be encouraging wild, extravagant, interesting maneuvers and styles in combat. This is a lot more entertaining than ordinary, plodding swing vs. swing combat.

Therefore, the DM should reward intelligent, creative efforts in combat by granting them bonuses to hit and damage.

Examples:
A lightly armored hero with the acrobatics non-weapon proficiency could charge a foe, then use his acrobatics to flip over him and strike him from the rear; the DM might give him a bonus to hit in addition to striking at a part of the target's body that is unprotccted by a shield.

A crossbowman could use a Called Shot against the rope holding the chandelier, causing the chandelier to come crashing down onto the villain's head: instead of suffering a massive attack penalty for such a preposterous shot, the DM might give the player an attack bonus for the surprise value of the attack, plus a percentage change for knockout, as per the "Attacking Without Killing" rules (Player's Handbook. Page 97).

A swashbuckler running up a flight of stairs with guardsmen in hot pursuit could tumble a stack of casks down the stairs behind him; the DM could give him a Pull/Trip maneuver against each one of those guardsmen, and even an improved chance to hit, for attempting this classic move.

On the other hand, a player might come up with a plan or maneuver that is merely foolish or abusive to the campaign. The DM can assign such a maneuver minuses to hit and damage.

Examples:
Rathnar's player decides that if Rathnar makes faces at an orc he is fighting, then the orc will become spooked and run away. When Rathnar attempts this, the orc proceeds to make faces right back at him, then begins the process of cutting Rathnar to ribbons.

Later, after some time at the healer's guild, Rathnar is in better armor and is in dire combat with another orc. Rathnar decides that he'll tuck and roll between the orc's legs, stand up behind him, and cleave him in twain from behind. However, his player has failed to consider that Rathnar is in bulky plate mail and knows nothing about acrobatics. The DM assigns Rathnar a stiff penalty to his Dexterity roll when Rathnar tries the maneuver. Rathnar ends up flat on his back, banging against the orc's legs with the orc looming over him, and the DM assigns the orc a bonus to hit Rathnar because of the hero's clumsy position.

Difficulty Determination

A good rule of thumb to use, when a player character tries something strange or daring in combat, is this: Don't say no to his proposal: just determine the difficulty of the maneuver in your head, give him a general idea of that difficulty, and let him try it.

An easy way to do that is to arbitrarily assign a "difficulty number" of 1 to 10 to any special maneuver. Then, have the character roll against whichever of his abilities (Strength, Dexterity, etc.) that seems most closely to pertain to the task... and subtract that difficulty number from his ability. If he succeeds in rolling equal to or less than his modified ability, he has succeeded in his task.

Example: Drusilla wants to try the same maneuver Rathnar was going to pull. She, too, has no acrobatic training, but is in light leather armor. The DM thinks that this will be pretty difficult for her (though not as difficult as it was for Rathnar, and assigns the maneuver a difficulty factor of 5 if she leaves her spear behind. It'll be an 8, if she tries to take her spear along on the maneuver. He tells Drusilla's player that it is difficult but possible, though it will be nearly impossible if she uses her spear. Reluctantly, she drops the spear and pulls out a short sword before attempting the maneuver.

Her Dexterity score is 13; with the -5 penalty, it's modified to an 8. On her combat action, she attempts the maneuver, and rolls 1d20 against her modified Dex. She rolls an 8, and achieves it exactly; Drusilla rolls between the orcs legs, stands up behind him, and drives the short sword home before he knows what hit him. The DM gives her an arbitrary +4 to hit for the surprise value of the maneuver.

Someone with Acrobatics non-weapon proficiency might be able to perform that same tuck-and-roll with no penalty or with a penalty dictated only by the type of armor he is wearing. See Table 57 (Armor Modifiers for Wreatling) in the Non-Lethal Combat section. Those modifiers would work equally well in this situation.

Another thing to do when a maneuver will probably work automatically if the intended target doesn't see it coming, is to assign a difficulty number to the target's chance of seeing it. This difficulty could be a penalty or a bonus, depending on how obvious the maneuver is, and so could be from 1 to 10 in either direction. The DM would have the intended target roll 1d20 against his modified Intelligence, and if he rolled equal to or less than that number, he'd see the maneuver coming and be able to avoid it. If he failed, the DM could give the attacker ordinary chances of success, or even make the attack an automatic success.

Example: Amstard is in a street brawl with a big brute of a warrior; they've been punching the daylights out of one another, and Amstard has just been knocked down. His player announces that he's trying a classic trick: He'll inconspicuously pick up a handful of sand and, as he's rising to return to the fight, he'll dash the sand into his opponent's face, blinding him.

That's a reasonable trick to try. The DM decides that the brute's chance to figure out Amstard's maneuver is directly proportional to Amstard's finesse in scooping up the sand. He tells Amstard to roll against his Dexterity, unmodified, when picking up the sand... and the number he makes his roll by will be the brute's difficulty number in seeing it coming,

Amstard's Dexterity is 13. He rolls a 10 on 1d20, making it by 3. The brute's Intelligence is 10; with the difficulty of 3, his modified Intelligence is 7. Secretly, the DM rolls 1d20 for the brute, achieving an 8; the brute doesn't see the mancuver coming, but Amstard's player can't be rold that until Amstard is committed to his maneuver.

Amstard now throws the sand; this counts as an attack. The DM gives him an ordinary attack roll to succeed. Amstard successfully hits vs. the brute's AC, and now the brute is temporarily blinded...

That's how the thought process works, anyway. The players should have the opportunity to try just about any maneuver or approach they can imagine, and the DM should figure out how likely each try is of success. Nothing should be impossible to try just because it isn't specifically covered in the rules.