Combat Encounters That Go Beyond Hack & Slash

Jay Barnson has updated his Tales of the Rampant Coyote blog with a list of seventeen "tricky" combat scenarios that he plucked from older Dungeons & Dragons modules while scouring for RPG design ideas.
5) Avoidable combats - battles which smart players can avoid completely by using their brains instead of their swords. There were often varieties of monsters coming and going in those old dungeons, which necessitated some loose agreements between them. The players could often exploit this situation. Using the correct password, or simply bribing the bored ogres might be enough.

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14) Non-Lethal Attacks - The enemy launches a quick raid set the party back (and gain treasure) rather than to kill them. It may be a quick robbery to deprive the party of equipment (or the functional equivalent via a Disenchanter or Rust Monster), or an attempt to lure / force the party into a trap, or simply to get them to waste spells, potions, and charges on magical items for an all-out battle that doesn't happen until later. Another example is an entirely illusionary encounter, which again may cost the party resources.

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16) The No-Win Scenarios - Like #5, but this is a battle which - if pursued to the ultimate conclusion - is for all practical purposes unwinnable. The only way to win is - not to play. Or rather, to find the alternative means of defeating the enemy. Players (and Captain James T. Kirk) hate these, but usually only because they don't realize its danger until too late. Presented carefully, I believe it is still a valid and enjoyable encounter.