When a game nears the end players usually choose one of two choices: to quit the game when they believe they can no longer win or to stay in the game and fight until the end when they are eliminated. That is usually how most games go. Sometimes players quit the game really early which is a surprise because you believed the game was far from over. Other times players will stay in the game until you kill off their town and expansions but don't really put up much of a fight as they are losing. But another class of players has discovered another choice: to delay the game as much as possible until their opponent forces them from the game! They seek to stay in the game as long as possible at any cost. Their reasoning is usually either a competitive spirit or a desire to make it as painful and annoying as possible for the winning player to receive their win. "You'll have to earn your win" says one of these players. Some people might view this as being a sore loser and certainly that is true but the people that delay games view it as war! No Retreat! No Surrender! This page contains more information about this situation from both sides.

How to delay the end of a game

In Warcraft II it was much easier to drag a game out. Players had to eliminate all units and buildings or the player had to quit to receive their win. "Hide the Peon" became a common strategy. Players even made it funny by building walls around their Peon. StarCraft used a lot of cloaking or invisibility which prompted designers to change the victory conditions to: eliminate all of the player's buildings. They did this because otherwise players could hide invisible or cloaked units around the map and other players might not be able to find them or have the resources to get detection to find these hidden units. Warcraft III continues with that condition for similar reasons but includes the rule of eliminating all team member buildings for team games.

Undead really have the hardest time delaying a game since they can't build Ziggurats off the blight. About all they can do is build some Necropolises around which is easy to spot so we won't talk about them.

Hide The Farm
Players who wish to delay the end of the game need to have at least one building left to avoid being eliminated. This means that they will hide farm buildings (Farms, Moon Wells, or Orc Burrows) around the map.

Tips:

It's important to hide the farms in the best places possible. Pick out of the way locations where other players are unlikely to look. You may even try placing them in opponent's bases where they might not find them.

Goblin Zeppelins are the best for hiding farms. Place a Catapult, Ballista, or Mortar Team in the Goblin Zeppelin along with some workers. Unload these siege units and use them to clear away trees so you can build a farm. Using this method you can place farms in areas that players can't really reach without air units, a Goblin Zeppelin, or by clearing a lot of trees out to get there.

Ask teammates for all of their resources so you will have plenty of resources to build farms.

The game is over when your farms are eliminated so continue to build them until you run out of resources or lose your workers. If the enemy kills one farm, you can try rebuilding it again after they have left the area. Some people never think to go back to a location after clearing it.

Night Elves: Hide The Ancient
Night Elf players can use the Ancient's Eat Tree to clear a path through the trees with their Ancients. They can use this to move the Ancients to locations deep in the trees that are difficult to find. They can also simply root their Ancients among the trees and attempt to blend in. People who do not toggle minimap allied colors and use their minimap often fall for this trick.

Guerilla Warfare with Heroes!
If you want to delay the game you have to make it more interesting than just building farms over and over. Save your Hero from being killed and use it for hit and run attacks. This will keep the enemy interested in finding the Hero and distracted from finding the farms which will further delay the game.

Find single targets to hit. Use your hero to kill one unit then run for it before the enemy responds.

Attack their workers on Gold and Lumber then run for it.

Get a Goblin Zeppelin and use it to do hit and run attacks with your hero. Land, attack, then get back in the Goblin Zeppelin and run away.

Your best tool in Guerilla Warfare is the Goblin Merchant. Buy Invisibility Potions. If the enemy does find or trap you use an Invisibility Potion. Then go back to the Goblin Merchant and buy another Invisibility Potion. Buy Mana and Healing Potions too which can help you solo a lot easier.

Dealing with people who delay the game

Toggle Minimap allied colors
First click on the crossed battle axes button to the right of the minimap. This will turn the enemy red on the map. This will allow you to easily see enemy buildings and units on the map when they travel through areas you can see.

Reveal the Map
Use everything at your disposal to reveal every bit of the map. Once the map has been revealed and using the minimap the enemy won't have anywhere to hide. This is not hard to do using flying units, ground units, and spells.

Orcs and Humans can build towers around the map. If the enemy tries to travel near them with their worker they will be killed.

Use a Goblin Zeppelin to scout or use the Goblin Laboratory's Reveal option to reveal the map.

Orcs: Use Wyverns, Witch Doctors to put Sentry Wards all over, and Farseer's Far Sight.
Humans: Use Gyrocopters, Gryphon Riders, or Mortar Team's flare to scout the enemy.
Night Elves: Use Priestess of Moon's Scout, Huntress Sentinels, or Hippogryph Riders to scout.
Undead: Use Gargoyles or Shades to scout the map.

Build flying units
Build flying units so that you can easily and quickly scout the map. Use way points to set up patterns around the map. You may have to kill Creeps in the way so that they do not kill your flyers.

Use Invisibility Detection
If the enemy keeps doing hit and run attacks with their hero use invisibility detection to find them.

Defend the Neutral Buildings
Build Towers at the Neutral Buildings and cover them with invisibility detection. This will keep the enemy from using them.

Catch that Goblin Zeppelin
Chase down the Goblin Zeppelin using flying units. You can also trap it with anti air unit spells such as Storm Bolt, Ensnare, Slow, and Web.

Conclusion
Using these methods it shouldn't be difficult at all to find the last of the enemy buildings if you really try. If you don't make a serious effort using the above methods then the enemy may drag the game on. It shouldn't be too difficult to find someone who is trying to hide.

You can also just alt tab out and let the game go. You do run the risk of the player finding some way to win but it might also cause the person trying to hide to get tired and give up. The person trying to hide could also do the same to you however and whoever's connection lasts long enough wins the game =)