Aiming an attack.

[Hoolix]

Not sure if this is really possible for 4e as I can not find anything about it. I haven't tried it in combat yet as I haven't felt threatened enough to "go for broke" yet. (Though a dumb move on my part nearly cost Scrag his life in a fight with a few spiders) Anyways back to my question; say we are fighting a Cyclops and I want to "aim" for his eye to blind him. What kind of penalty would that bring?

[Mgrancey]

There are no official rules for it in 4e, as they gameplay system is setup like an MMO. However, Kobold Quarterly did suggest some rules that support this idea, a monster has vulnerable areas that have slightly different defenses and are considered X% portion of HP and destruction/damage of said area has effects upon the monster. I will have to look for it to give you more information about it.

[zapoqx]

Only 3 examples come to mind from the different DMs I've been with.
Very Large Mechanical Statue Creature, Damage Resistance. Target Knee in an attempt to test resist strength. Successful hit meant Critical hit. (Ironically, while DM had no idea about Arrow to the Knee joke at the time... conveniently, we had a ranger going next that was archer spec.)

Enemy creature with several tentacle-like limbs. Captures a player. Target limb holding player to help him break free. Higher AC to account for smaller target. Success: Damage and huge impact method to break free (I believe it was +5 to escape).

Player is completely out of the fight due to a stun and being locked out cause of bad saving throws. No other enemies to target with the secondary attack of a lightning based attack. Asked and used secondary lightning attack to... ahem... jump start her. +2 bonus to saving throw and broke free immediately.

As you can see, all up to the DM in each case. As Mgrancey stated, there is no official rules for it. If I tried channeling them without asking them right now, I'd dare think they would decide on higher AC with ranged attack to account for aim time. Melee? I don't know.

[gmkieran]

If I were GMing that situation, I would increase AC by 4 to 7, depending on size/accessibility of target (Cyclops' eye probably a 6, Cyclops' knee 4, Goblin's knee 5, Goblin's eye 7) and arbitrarily set a number hitpoints for that target; if the hit exceeds those or scores a crit, the target is out of commission with all appropriate penalties (Cyclops is blind -5 to hit or the Goblin is lame 1/2 movement).

In the end it comes down to come up with a house rule that makes sense to everyone playing and implement it.

Cheers!
GMK