Redonkulously early in the morning. Often it is still dark out. Commonly used when one must wake up early after a night of drinking, or getting up to go on a trip. Also can be referred to "Oh dark hundred"
Person 1: "Dude, what time do we have to get up tomorrow?"
Person 2: "The freaking ass crack of dawn."
The asscrack of dawn is the time of day just before the crack of dawn when it is just about still dark; it is the time at which one might get out of bed if attending an urgent appointment at the crack of dawn.
John woke up at the asscrack of dawn with the intent to get to the shops just as they opened for the post-christmas sales in order to avoid getting trampled buy eager bargain-hunters.
A Shackteau is a humble, weather-beaten, structurally questionable shelter located in a spectacular or highly coveted place—Wales, Jackson Hole, Sun Valley, Crested Butte, coastal Maine, the Alps—where the building itself may be worth almost nothing, but the dirt, view, access, and mythology make it absurdly valuable.
In use:
Shackteâu - We thought it was an abandoned shed until the realtor called it a rare alpine Shackteâu with unobstructed views and listed it for $2million.