Diplomacy

Diplomacy is a board game involving dealmaking, surprise, treachery, and world domination: in short, the techniques of Diplomacy. In anticipation of a dinner party, here is the short version of the rules (according to me) as well as a stern recommendation to get out there on the internet and read up: this is not a trivial game. However, with some effort, the rules can be condensed as follows:

1. Just one unit (Army or Fleet) in any province at a time.
2. Some regions, equipped with a star are supply centers, and will support (feed and equip) an army or fleet. You pick. Obviously, control lots of these to have lots of armies.
3. Armies or Fleets can occupy coastal land, but ONLY armies inland or fleets at sea (duh).
4. Game sequence is a) diplomacy -> b) write orders -> c) reveal & resolve. During diplomacy you make deals with each other. Writing orders is done by secretly specifying, for every unit that is to act, if & where it will go, and what it will do. Then everybody throws down at once and all work together to figure out what happened.
   
5. Bad or illegal orders devolve into orders to Hold position.
6. Orders you can give are Hold, Move(& thereby possibly Attack), Support or (if you're a fleet) Convoy. These are your only "verbs" in orders.
   
7. In all engagements, might prevails: the most units wins. If equal forces meet it's a standoff, and everyone holds.
   
8. Even friendly units can't swap position: borders between regions can "handle" only one unit across their borders per turn. A Convoy operation can literally circumvent this stricture.
9. To win a battle, Support either a Hold or an Attack (and you must specify which you intended.)
10. You cannot successfully Support if you find yourself Attacked from the flank.
11. Losers are dislodged, (after rendering any support they may have been called on to provide).
12. Fleets in ocean (not coastal zones) can convoy 1 Army across the water, and with multiple fleets, any oceanic distance may be traversed in a single turn.
13. A standoff occurs when equal forces attack/support a single (possibly empty) province.
    
14. Dislodgement of any unit conducting a Convoy operation causes the transport to fail.
15. After losing, dislodgement means you must write a retreat order and carry it out immediately, and you may not retreat to (a) your attacker's land (b) any occupied territory (duh) or (c) empty region that experienced a standoff.
16. Every two turns (winter and summer are the metaphor here) you disband or add units according to the starred provinces you control.
    

There are some other rules, one of my favorite being, An army with at least one successful convoy route will cut the support given by a unit in the destination province that is trying to support an attack on a fleet in an alternate route of that convoy. Bone up on that one before the game, please, because it comes up kind of a lot.