Ask HN: Oldest code you have written that is still in use?
People still play the Warcraft III map I made in 2006, mostly in Russia.  It relied heavily on an extension of the scripting language called vJass created by a genius eastern european hacker named Vexorian and was one of the most advanced of its type for a while.It was also ported to the DotA 2 engine, where it has millions (!) of subscribers.