On Bourke Street where the David Jones department store now resides you can still see a marble plaque reading Buckley and Nunn for the hat shop that first sold its wares there. This plaque gave rise to the saying, "You've got two chances: Buckley's and None," meaning no chance at all. This became shortened to, "You've got Buckley's chance" or just "Buckley's". The idiom is uniquely Melbournian, but has spread to the rest of Australia.
In a similar vein is a "Clayton's ____", such as a Clayton's date or a Clayton's dessert. This comes from an ad campaign run here about a brand of low alcohol liquor which went, "The drink you're having when you're not having a drink." So the above translates as "The date you're having when you're not having a date" such as when you go with your sister to a dance or "The dessert you're having, when you aren't having a dessert" such as a serving of low fat cottage cheese. This leads me to my own description of virtual reality, "Clayton's Reality (TM): The reality you are having when you aren't having a reality."