Why DOOMSDAY you will ask? Well, we had that 12.12.12 date, when we would all die from horrible events... and we were in so so great danger that the AITeam decided that we should celebrate the death avoidance during the whole 2013. So.. that`s the reason.

Link download:
Dota 6.77c AI 1.4b
DotA v6.77c AI 1.4b.w3x