Callahan's Key — Spider Robinson

The universe is in desperate peril. Due to a cluster of freakish phenomena, the United States' own defense system has become a perfect doomsday machine, threatening the entire universe. And only one man can save everything-as-we-know-it from annihilation.

Unfortunately, he's not available.

So the job falls instead to bar owner Jake Stonebender, his wife, Zoey, and superintelligent toddler, Erin. Not to mention two dozen busloads of ex-hippies and freaks, Robert Heinlein's wandering cat, a whorehouse parrot, and misunderstood genius-inventor Nikola Tesla, who is in fact alive and well....