Yes, I played and still seasonally play Dungeons and Dragons.  For those not in the know, Dungeons & Dragons (D&D) is a game of imagination, generally set in a fantasy medieval age where where the rules serve as a framework but the actual game is created dynamically by interoping the Dungeon Master's general plan for how things will go and the players' choices.  Think choose-your-own-adventure book for those that read them.  The players run around, get roped into a plot, solve a mystery, work together, slay baddies, get loads of treasure, go on to glory--you get the drift.

As the Dungeon Master (DM), you basically sacrifice you own enjoyment as a player for a different kind--you get to create the adventure rather than play the role of the adventurer.  And that's where we begin to see the two worlds--D&D and adventure racing--come together (you may draw your own analogies from the lessons of D&D below). 

D&D is all about having fun.

There are no official rules for "winning" D&D, because the players are all simply working together to create the plot of the game.  There are goals, successes and disappointments, etc.  There is a start and a finish to each session or campaign, just as there are beginnings and ends to chapters within books and the book itself.  But you cannot "win" at reading a book, there's really no such thing.  Some read faster, others slower; but in the end the most important thing is the story.

The DM and the players are friends.

How else would the goal of "having fun" be met?  The DM has to know the players, know what they do and do not enjoy, and take them through a mix of challenges and adventure such that when the adventure is over, they have accomplished something.  A sort of a symbiotic relationship during gameplay in order for everyone to have fun.

Ultimately, everybody wants the players to be challenged, but not wiped out.

The players should have a well-founded fear for their lives, knowing full well the gravity of some of the choices they must make.  However, there must also be a realistic chance of survival--that is, if they avoid boneheaded mistakes and work together.

There are a lot of different player types the DM caters to/deals with:

• Reluctant Worry-Wart: Challenges the DM every step of the way, kicking, screaming, sharply criticizing, oftentimes mentioning what he or she would do as the DM, only to thank the DM profusely later after the adventure is over.
  
• Legalist: Argues endlessly about rules, what is and is not realistic, how the rules might be made to better represent reality instead of facilitate gameplay.  Oftentimes, the DM is constrained in other ways, unbenounced to the Legalist. 
  
• Unimaginative Rhino: Never wants to try new tricks.  Instead, wants to look at the challenge and attack it head on, even if there are numerous and apparently better options.  These players are generally a liability to the others, as their brash actions oftentime fail where the DM has designed a scenario requiring creativity.
  
• Mad Scientist: Only considers outlandish options that would DM would never have envisioned, because 99% of the population would consider them insane and/or terrible ideas.  Pretty much avoids any solution that is reasonable from the get-go.  These players are liabilities to the DM because if they can convince the other players to go with their ill-fated, long-shot plans, there is a chance the party will be wiped out completely and that's no fun for anybody.
  
• Happy-Go-Lucky: Only in it for the fun.  Enjoys the ride the entire time and afterward.  As a result, generally has fun.  Helps to refocus other players on the real reason they are playing, excellent mediator for the DM and the other players, because Happy-Go-Lucky and the DM's goals for the players are generally the same.
  
• Silent-But-Deadly: Makes no motions, comments, or otherwise until the right moment.  Then blows everyone away with an unexpected and effective strategy.  Be careful around these, as they are generally very experience, game-changers.
  

The DM is harsh, but fair.

If the rules are to be enforced, they better be fair.  They must protect both the players' and DM's interests.  If the rules are fair, they must be enforced without predjudice.  Nuff said.

There are lots of maps.

D&D combat strategy is all about the maps.  The terrain, the positions of the baddies and the player's characters, and the capabilities of each.  Strategy, and thus outcome, is oftentimes governed by the constraints of the map.

Usually folks that are wandering in the woods get waylaid by enemies.

A strategy that DMs often use to encourage the forward momentum of the plot is to use some mechanism to discourage the players from losing the plot.  This extra encouragement, usually in the form of the stick rather than the carrot, helps to keep the players focused on the objective.

The best DM is a player first.

Planning a successful adventure for the players oftentimes means putting oneself in their shoes.  A DM that is also a player has a huge advantage then, over DMs that are not.

Different DMs have different styles.

As a player, this is the most important thing--since all rulings and game development generally comes first from the DM.  Therefore, understanding the intent of the DM generally means greater success for the players.