Taken from the saying "It ain't over until the fat lady sings," commonly attributed to ex-Yankee ballplayer Yogi Berra.

Presumably, the "fat lady" in question is a stereotyped opera singer, replete in Wagnerian Rhinemaden garb. Ironically enough, the "fat lady" was usually singing the United States National Anthem, the traditional way to START a baseball game.

The Games is over

To show up to work late, hungover and/or still drunk. A term used by English speaking ex-pats living in Venice, Italy. The term is rumoured to have originated from being stuck behind a fat lady on crutches in the narrow streets of Venice, it was rumoured to have been originally an excuse for being late to work, the current definition has grown to incorporate being both late and generally unfit to work.

A pair of 8's in poker.

A feminine overweight person.

Meaning that nothing is gonna end till the very last point and till the very last options are gone.

This could be self explanitory. Actually, all you need to do is look at just about any SUV you see driving by, and you will see her in the drivers seat.