Cinematics

The curse and blessing of playing RPGs is getting to watch action movies and shows and picture how awesome it would be if combat was like that in games.

It is amazing watching those things and picturing your current character doing them. Called shots, one hit kills, amazing feats of strength and acrobatics; all these things heroes can do in movies but recreating them in games is incredibly difficult.

If a player wants to do something epic (which is usually not covered in the rules), what can a DM do? Saying no is a terrible idea. Players become very discouraged when they can't at least make an attempt to do something and may rapidly lose interest the game. However, awesome is rarely in the rule book.

In a recent came one of my players was in the jaws of a T-Rex, about to be swallowed and another player was in the branches of a nearby tree. Tree-Dweller wanted to leap from the tree onto the T-Rex and run along it's back and attempt to hit it hard enough to dislodge the Snack.

The jump, climb, and balance checks are in the rules and "easy" enough to adjudicate. The smacking of a dinosaur hard enough to make it drop its food is not so easy. However, DMs are not supposed to stand in the way of awesome from the players. Setting a damage threshold seemed the way to go. While he failed to do the required damage; everyone was on the edge of their seats for the outcome.

Unfortunately, this type of awesome requires a few things.

1. You need to be familiar with the rules. Enough to think on the fly and be able to extrapolate from very specific rules to almost completely, unrelated situations. 
2. You need to be open to suggestions from your players. Many minds are better than one. However, don't let suggestions take too long or the tension of the moment will be lost. 
3. If consensus can't be reached, make a ruling. Too often games drag because of rules disputes. You're venturing into territory that will never be explicitly covered by the rules. When the final ruling is made, players can either agree or disagree. If they disagree, continue the debate after the game. 

The most important thing is to try and work with your players on this. There will come points where you may disagree, but efforts need to be made to meet them at least halfway. Part of the fun is being able to tell stories about how awesome encounters were. And sadly, awesome is never in the rulebook.