Today's Google Doodle animation is in honor of leap year in the Gregorian Calendar. As you can see from the images below, legend has it that rabbit #29 jumps in between rabbits #28 and #1 without disturbing their sleep. Whether any of these cartoon rabbits are related to Inspector #5 is not clear.
A bit more seriously (but still in the realm of fiction) is the art and science of timekeeping. The leap year, occurring once every four years, is actually a transannual correction on the 365 day year. As it actually takes 365.25 days for the Earth to make a single orbit around the Sun, the Gregorian calendar falls short. In fact, there has yet to be a calendar created that perfectly captures the length of a solar year. This brings us to a potential candidate, the well-known Stardate.
However, despite stardates being the primary mode of timekeeping in a fictional interstellar civilization, they are surprisingly fluid from one part of the galaxy to the next, and from one series to the next. But you can download a more stable version for your own computer, as the concept of a stardate is based on a standard mathematical model.
Regardless of the inconsistencies in the Stardate system, time travel occurred a number of times in the Star Trek franchise. As this is the 50th anniversary of the first season of Star Trek: TOS, it's a good time to look at instances of time travel in the Trek franchise:
Ex Astris Scientia, Time Travel in the Abramsverse
Memory Alpha Wiki, Temporal mechanics
io9 Blog, Six Theories Of Time Travel In Star Trek
Time travel tech, Trek style. COURTESY: ArsTechnica and Paramount Pictures.