[null and void]

As far as I know it's based on Callahan's Crosstime Saloon.

Said Saloon is found where you need it, when you need it, if you are VERY lucky, or exceptionally interesting.

[LongElegantLegs]

That’s the one! (thank you, and wikipedia!)
I read one when I was just a kid, and all I could remember about it was the final pun, wich was when somebody called the bartender “Justin, the Nick o’ time”...but now I see it was probably “the MICK o’ time”...Everything makes sense now...THANK YOU!