This one took some thinking back on. I have played in several long campaigns over the years. But the longest of them all was a departed friends Star Wars D6 Game. When I arrived at my first duty station in the army the first thing I did was get deployed to Somalia. I did not even get in-processed fully before I was in the air to another country.
As soon as I got back nearly a year later the second thing that I did was head directly to the base recreation center. When I walked in I discovered a wonderland of Gaming. There were RPG being played there at nearly all times when it was open, day or night. In short order I set to finding myself a group. I chose well because the friends I made that day were lifelong.
Even now hundreds and some thousands of miles apart we still talk. It was the military that brought us together but games that made us never forget one and other.

The game I joined was an ongoing Star Wars D6 game I joined a table with 6 other players. From the start I had concerns that the game might not end well. When I joined the group the GM pulled me aside and asked me how I would feel playing a traitor to the party. He wanted my character to be a spy for the empire. I loved the idea and said yes on one condition. I would get to decide when I would turn and how. He agreed and the stage was set.

Over a year of game time pasted and one day he pulls me aside again and asks me if I ever plan on turning on the party of if I had decided to go rogue. If I had he was going to begin searching out my character as a deserter. I laughed and told him I was playing the long game and I wanted to make it worth it. Soon after I would strike, nearly two full years of real-time later. Our players were at being hunted by bounty hunters and the empire alike. The Rebel alliance had sent us on the most dangerous mission yet. Everything hinged on finding the location of the Empires secret battle station the Death Star!

As we closed in on the final few sessions I began giving seeds to the GM. Informing imperial forces and bounty hunters to our locations. With everything in place we landed on a nearby moon and I struck. First I convinced the party to split into smaller groups. I then set about my first ever inter party conflicts in the history of my gaming.

I joined one group of players as they were about to enter a turbo lift. As the doors begin to close I tossed a Thermal Detonator into the lift ending two of the party. The whole table looked at me in shock. They had known for some time that there was rumor that I was a traitor but in sessions past I had convinced the party that I was indeed on their side. Untill this very moment none of them had suspected me for months. With planed precision I moved my plans into action. Calling squads of Stormtroopers to my side and rounded up or killed the remaining players. The whole table tense with each round that went by as they tried to scramble off the planet. Only one would get away that day.

When the game was over. I looked around the quiet table fearing I might have lost some of the friends I had made at this table over my ultimate treachery. Instead what I got was a resounding “THAT WAS AWESOME!” So my longest played game is also one of my best gaming memories.