The broader, most accepted, defination to c'est la gare can be found in its urban French roots. Though, in the past, it referred to an arrival or departure of a train, today it is often used as a expression of waiting for the arrival of or departure of a pending event.
An example would be the departure of your hot girlfriend. You might say : c'est la gare, as you watch her walk away. You may also need to say: c'est la gare, as you are being hauled away in handcuffs following a beat-down you took after arguing with the cops. In either instance, you would be correct and a master of the "French" vernacular....
by Squal Pascal May 15, 2011