Time Travelers Strictly Cash by Spider Robinson
Human or otherwise, regardless of race, creed or dimension of origin, if you're looking for a good time in a place where the beer is always flowing, and the stories always out of this world, step up to the bar at Callahan's. There'll be tales - Oh, are there tales! Like the one about a loud-mouthed time traveler who capitalized on a rip in the space-time continuum; or the one about Ralph the talking, gin-drinking German Shepherd created by a demented genius shrink. But don't believe us. Ask Ralph. He'll tell you himself. Also don't forget to watch out for the deadly toasts - especially the Melba toast! And above all, remember... Time Travelers Strictly Cash.