Callahan's Legacy

It's more than twenty years since Spider Robinson revealed the existence of Callahan's bar, and the original bar is gone. Mike Callahan is gone, too, but not forgotten. His spirit lives on in the new bar, called Mary's Place, named for his daughter. On this particular morning, Jake Stonebender, proprietor of Mary's Place, wakes up and crawls out of bed, not realizing how big a mistake he's made. It's going to be one of those days.
It's not that his lovely wife, Zoey Berkowitz, is nine and a half months pregnant. Maybe it's the early morning knock on the door and the incredibly ugly person who greets Jake and startles him so badly that he spills Zoey's urine sample - all over the misshapen mistake of nature standing in front of him. That's when he realizes that this is going to be a day of reckoning.
After this inauspicious start, the day takes a turn for the worse when a huge storm rips the roof off the bar - and moments later drops another, better roof on it. Then the guy with the suitcase full of hundred-dollar bills arrives and starts making them into paper airplanes that he cheerfully launches toward the fireplace.
That's when Mary Callahan and her husband, Mickey Finn, show up, unconscious, appearing literally out of nowhere. And they have bad news. They've come to warn the barfolk that a three-eyed, three-toed, three-everythinged purple monster - the nastiest, most vile servant of the Beast - is going to descend on them within mere hours. The fate of life on Earth will depend on the collective karma of the bar when they confront this all-powerful monster. Through laughter and tears, with puns powerful enough to melt Formica, the most famous bar in all of spacetime is going to rock this night...but will the Earth survive?