Mine is really old, back then I was trying out roleplaying and we gathered a group of people to roleplay on a Warcraft 3 custom map called Waugriffs COT RPG. It was basically a huge map with simple mobs of varying levels spread around. Players chose one of the numerous heroes (powerful units that can level up and gain much more abilities compared to most other units) and began their journey. In the town center in the middle you could also choose to acquire blueprints for an empire of each vanilla race (including campaign ones) and custom races.
Now, I really liked the Naga and chose to build a Naga empire. My Naga kingdom was built on a secluded island on the west you could only access with flying units or through a portal and usually attacked quick and deadly, earning my hero the nickname "Viper" within time. Eventually, when I conquered the highest-level area of the game, a mountain on the most southeast part of the map, it turned into Viper, Lord of Apex, and then to my current name, Lord Vipex.
Also while typing I had nostalgia overflow and really needed to dig the map up again. Time for an new journey [:
While I have lots of good memories attached to it I actually wanted to get myself a new pseudonym, though I can't find one that fits right.