Why RED and BLU fight

I have a theory that encompasses all the maps into the story.  Please post your own theories if you have any.

    A long time ago Reliable Excavation Demolition (RED) had a very succesful buisness demolitioning old buildings so that the Builder's League United (BLU) could put up new, better buildings in their place.  This relation ship had gone on for a long time until BLU realized that they could fix up the buildings at a lower cost to the owners and then get more buisness than RED.  When RED caught wind of this they became furious.  BLU and RED's long lasted peace was now broken because of BLU's greed.  RED wanted to intimidate BLU back to helping RED, so RED hired a team of nine mercanaries.  They got these mercanaries from all over the world.  They had the mercanaries attack BLU's headquarters.  Unknown to RED though, was that BLU was a business that ran deeper than building buildings, they built WMDs, so BLU already had a team of mercanaries (which just happened to be exactly the same as RED's mercanary team) in their HQ.  When the BLU's spotted the RED team coming to attack them, BLU immediatly sent out a counter attack.  
    
    At the end of this battle, the spies for each team had gathered intellegince that the other side had a hidden base beneath one of their corporate offices, which just happened to be fifty feet apart.  Both teams decided to attack the others office in order to steal intelligence about the other's plans.  The preciding battle was forever known as the battle at 2fort.  Upon gathering enought intel on the BLU's, the RED's discovered that the BLU's had a massive WMD plant at a Hydro-electric plant.  Now the REDs decided to set up shop not too far from the BLU base.  There RED also set up a WMD to attack the BLU base.  When BLU scouts discovered the REDs, BLU mounted a massive attack of the RED base.  The REDs were quickly annihalated and their WMD was hijacked by the BLUs.  
    
    After this victory, the BLUs learned that the REDs owned both a Granary and a Gravelpit from which they partially ran their opperations.  BLU mounted a double attack on both of these places.  After a fierce fight at the Gravelpit and an easy fight at the granary, BLU controlled both of these assests.  BLU also had info on an abandon trainyard that the REDs called The Well.  After capturing the entire facility, the BLUs were surpirsed to see that the REDs fought to get important intelligence from the BLUs.  The BLUs didn't care though because there was nothing the BLUs had that the REDs didn't already know.  The BLUs fought for the REDs intel and upon acquiring enough, crushed the remaining RED forces that were stationed at The Well.  

    From this intelligence the BLUs found another one of RED's bases, coded named Dustbowl.  They also learned of a RED base out in the Badlands.  BLU attacked the Dustbowl compound first by following the railroad tracks at The Well all the way to Dustbowl.  Each section captured was another section closer to irradicating the REDs from Dustbowl.  After capturing Dustbowl, the BLUs learned of the main headquarters of RED.  They decided they were going to destroy the REDs once and for all.  The BLUs wanted to use a mininuke to destroy the REDs but they lacked the proper equipment to do so.  Lucky for them, the RED base in the Badlands had the necessary equipment to do such a thing.  After a very long and tiring fight for the Badland compound, the BLUs were triumphant.  

    They then set out to build their minnuke.  When it was complete the BLUs used the Dustbowl compound to launch the attack.  Using

It says somewhere that RED and BLU are actaully intelligence agnecies, working against eachother.

Really where?

I've always wondered why they fighted!!

Neat story, but I think there is some history about them out there on the web.  Also, its very TLDR, so separating each battlescene into a separate "paragraph" would make the story flow a bit more.  I like how you linked each map together, and how you kept the concepts of each battleground in check (making BLU attack, and RED defend).

From Half-Life 2.net forums:

Blu and Red were originally bitter rivals in the food-production industry. Blu produced various carbonated and alcoholic beverages while Red produced bread and pastries. The rivalry began when Red began reviving an ancient Babylonian recipe for alcoholic bread, which Blu saw as muscling in on its turf. To add insult to injury Red began promoting its new product with an extremely anti-Blu marketing campaign with such hurtful slogans as "blu sux0rz" and "blu is ghey lol". Blu responded by introducing a series of cola-flavoured cakes. Although both products proved to be wildly unpopular, a bitter rivalry was formed.

During the Second Great War soldiers discovered that both company's products made for excellent impromptu weapons. Blu's soda made for an excellent grenade when shaken well and Red's baguettes could be used as a truncheon for lethal effect. Both companies experienced exponential growth during this period and by the end of the war they were both looking to expand into new areas. Due to the incredible advances in electrical technology being made at the time, both companies began to invest in communications technology.

In the year of our lord 1951 the League of Nations issued an announcement: They were to give near-unlimited funding to the first organization that could create an efficient and economical means of launching and maintaining a global communications satellite. The desperation for this funding has resulted in research into advanced weapons technology and military training facilities for use of corporate espionage. These attempts at sabotage have degraded into all-out brawls between rivals armies; bred, trained and raised to die for their company, even if they do not know the reasons.

Neither company knows how close Tan, a breakfast-cereal producer, is to completing its rocket.

paragraphs please.

Haha, that would be funny if there was Tan..

what would it stand for though?

I'd say there is little backstory to it. RED and BLU are fighting over a contract for some rocket/satellite/weapons technology. They own large shipping businesses, a hydroelectric plant, and produce beer. They own some mining businesses. They both want the contract badly, and are resorting to corporate espionage and sabotage to get it.

Tan = Trustworthy Architecture Network

i just think its a natural thing between the colours just look at footy
liverpool vs everton
man utd vs man city
arsenal vs chelsea
i feel its a natural hatred between colours COME ON LIVERPOOL!!!!!