Popular 'deal a day' website, woot.com, strays from its standard one item format about once a month bringing its customers many consecutive items. When one item sells out, it is replaced by another item almost immediately. This can go on for well over a day until it ends without warning, often with woot's infamous bag of crap!
A woot-off is signified by two flashing red lights below the item. As long as these lights are present, the woot-off is still going on.
David: "Great! I'm not getting any sleep tonight!"
Billy: "How come?"
David: "There's a woot-off going on! I HAVE to stay up!"