Well, here is my system that we've been using for the past few months.
[sblock]SKILL COMBAT
1. Make Contact
• Encounter Distance: In a situation where the encounter distance is unknown, roll on the following table to determine how far apart the groups are:
Terrain Type : Distance in Squares
Dungeon: 4d6
Plains: 1d10x10
Hills/Moor/Mountains: 3d10
Forest/Swamp: 3d8
Road: 1d20+10
• Surprise: If one or both groups are unaware of the other, there is a chance for surprise. If both sides are aware of each other, both sides may act in the first round.
i. Ambush: A side trying to ambush rolls Stealth vs. the Passive Perception of the other side. The character with the lowest Stealth modifier makes the roll; others may Aid if they take an appropriate action. This can result in both sides gaining Surprise.
ii. Lookout: A side that is actively keeping watch may roll Perception. There is only one roll; others may aid. The character who rolls is the one who is taking the most appropriate action.
iii. Surprised: Characters who are Surprised may not act in the first round. They grant Combat Advantage.
• Reaction Roll: If the monster's disposition to the PCs is unknown, roll on the following table to determine their reaction:
2d6 Roll:Reaction:Successes
2:Immediate Attack:--
3-5:Hostile, possible attack:8
6-8:Uncertain, monster confused:6
9-11:No attack, monster leaves or considers offers:4
12:Looking to make friends:2
• Negotiation: If the two sides talk it out, run a skill challenge. The number of successes needed before 3 failures is determined by the reaction roll, as indicated in the above table.
2. Beginning of Round
• Any beginning of round things take place here; standing in a zone, for example.
3. Declare Actions
• Free & Clear; only until everyone's happy with their action do you proceed. Players may change their action depending on what the other side has declared.
• If you can do it, you can do it, but you need to declare it. This includes declaring any immediate actions or triggered actions, such as OAs, a Fighter's Combat Challenge, a Shield spell, etc. If you don't declare it as part of your action you don't do it; you can't add an action, no matter its type, later on in the round.
• You can't wait to see what happens in the round - no delaying actions. You have to take your chances with the roll.
4. Determine Modifiers
• Modifiers to the d20 roll are determined based on the description of the action. All applicable modifiers are added. Use the following to determine what the modifiers are:
• Select a single stat modifier to apply. The stat that is chosen is the one that's most appropriate to the action.
STR Strength and raw power.
CON Endurance and physical stamina.
DEX Physical quickness and precision.
INT Mental quickness and reasoning.
WIS Mental stamina and willpower.
CHA Social power, force, and presence.
• If a power (exploit, prayer, or spell) is used, most of the time the stat associated with that power will be appropriate, though not always.
e.g. shoving your hand down the throat of a monster and casting Lance of Faith will use STR, not WIS.
• Select one of the following modifiers, choosing the one that comes first in this list:
Action:Modifier
An attack with a weapon or casting an offensive spell (e.g. swinging your sword; casting Magic Missile):Item (proficiency + magic), plus any class bonus (e.g. Rogue’s Weapon Talent)
Directly affect an opponent (e.g. shouting at your opponent to surrender; examining his fighting style for a weakness):Skill
Moving (e.g. trying to climb a tree; turning tail and running; attempting to hide):Skill
Defending yourself (holding your shield up; parrying a blow with your sword)

efence (1d20 + Defence – 10)
Anything else (e.g. Trying to cast Healing Word before your friend is killed; trying to shut a door before your foe can come through it):Initiative
• If you have a skill that applies, add in a single +2 bonus.
e.g. Moving into the shadows to hide and then casting a spell will give you a +2 bonus if you have a skill that applies to hiding in shadows.
• If your action gives you an advantage, add in a +2 bonus.
e.g. Flanking, surprise, prone foe, higher ground, etc.
5. DM sets DCs
• Based on the description of the action, the DM sets the DC for the action. Select the first that applies from the following list:
Action : DC
You try to push, overpower, or manhandle someone. : Fortitude
You try to touch or tag someone. : Reflex
You try to attack someone's mind or convince someone of something.:Will
You try to hurt someone physically. : Armour Class
You are matching skills with someone. : 10 + their skill modifier
You are trying to do something else. : DC set by the opposition’s level, using the table on page 42 of the DMG. A Hard result indicates a stunning success, a Moderate result indicates a marginal success, an Easy result indicates a marginal failure, and below Easy indicates a large failure.
6. Take Action
• Everyone rolls at once. Actions are simultaneous, there are no turn-by-turn actions.
• Actions are resolved in order from highest to lowest modified roll, if it matters. If two or more rolls are tied, determined resolution order by rolling Init.
• When one action has multiple targets, the first roll determines the order. When your action goes off, roll the rest of them. This goes for things like OAs and other triggered actions like that.
7. Resolve Actions
• Skill checks are resolved in the usual manner.
• Damage/Hit Points:
Monster Hit Points by Role and Level
Level:Minion:Normal:Elite:Solo
1-3: 1 : 4 : 8 : 20
4-6: 2 : 6 : 12 : 30
7-9: 3 : 8 : 16 : 40
Brutes add 1
PC Hit Points by Level
Level : 4 : 5 :6+
1-3: 6 : 8 : 10
4-6: 9 : 12 : 15
7-9: 12 : 16 : 20
Add 1/2 CON modifier to the number of hits.
Monster and PC Damage
Level Base Damage
1-3 2
4-6 3
7-9 4
Action : Damage Mod
At-Will power or Basic Attack : +0
Power that adds two stats to damage : +1
No modifier to damage : -1
No damage dice : -1
Using d4s for damage : -1
Using d12s for damage : +1
Critical hit (with high-crit weapon) : +1 (+2)
1-5 ongoing or extra damage : +1
6-10 ongoing or extra damage : +2
11-15 ongoing or extra damage : +3
16+ ongoing or extra damage : +4
2[W] or two dice of damage : +1
3[W] or three dice of damage : +2
4[W] or more, or 4+ dice of damage : +3
Half damage on a miss : ½, round up
Hunter’s Quarry, Sneak Attack, Warlock’s Curse : +1
You strike at a vulnerable spot and your opponent has no way to avoid the attack : +1
Temporary Hit Points : Temporary Hits
1-5 : 1
6-10 : 2
11-15 : 3
16+ : 4
8. End of Round
• Morale checks, if necessary. A Will roll against an Easy DC of the party's level. Can be triggered by actions taking during the round, as well as those listed here.
Triggers : Modifiers to DC
Leader bloodied : +2
Leader screwed (blinded, stunned, dazed + immobilized, etc.) : +2
Leader dead : +4
1/2 monsters bloodied : +2
1/2 monsters screwed : +2
1/2 monsters dead : +4
Per PC bloodied/screwed : -2
Per dead/unconcious PC : -4
• If the morale check is failed, the monsters change their tactics - running, surrendering, attempting a parley, bribe, blowing limited resources, falling back, etc.
• Saving Throws from effects ongoing from the beginning of the round. If a saving throw was granted during the round, or a monster can make an immediate saving throw (eg. hobgoblins), they can do that now.
9. Repeat Steps 2-8
10. Shake it Out
• Actual hit point damage is determined.
Round all damage into healing surge amounts, rounding up (eg. A fighter with 10 hits/28 HP takes 2 damage; that's 1 healing surge, or 7 HP.)[/sblock]