1. when a situation or a task at hand goes bad.
2. An event that results in a displeasing outcome.
One arrives at a party and finds the situation bad, uncool, boring, lame and/or gay. One would describe the party as a "shitfest". Normally used in context as such, "What a shitfest!"
a week of pure mayhem and total craziness. DJ, no pants, blacklights, jello shots, cowboys and indians, and unlimited booze. Survivors of this week will have hilarious memories, this week may cause broken walls and no memory from the past week.