MINECON 2010 or MinecraftCon 2010 was the first MINECON, and had 2 parts.
MinecraftCon 2010 was a spontaneous gathering of Minecraft fans on August 31, 2010 in Bellevue, Washington. It was conceived by Notch after expressing in a blog post several requests for a meet-up by players and had called on the community to organize one with no specific choice of venue. While Notch had labeled it "Minecraftcon 2010", it is a bit of a misnomer as it implies a formal convention not unlike that of a typical gaming or anime convention. This thread on the Minecraft Forums was an unofficial organization point for the convention, complete with YouTube videos and pictures afterwards.
MINECON 2010 was a gathering of Minecraft fans on a Minecraft Classic server. This thread on the Minecraft Forums was an unofficial organization point for the Con. There was a spleef tournament, a building competition, and an obstacle course race. (There was also initially going to be a griefing competition, but it was cancelled.) There was also a signature wall that 167 people signed, including Notch. Notch also confirmed Herobrine would be in the game, probably in a Seecret Friday update. But that has never happened and has decided against it ever since.