Google Maps has been home to game-themed Easter eggs in the past, and that will be the case again for the next week. To celebrate Mario Day, Google will add a limited-time option to introduce a Mario kart as your position indicator when using the GPS navigation app.
A new update for Google Maps on iOS and Android is in the process of rolling out. With it installed, you'll be presented with a ? block icon next to the Start button when looking up directions. Tap that, and the navigation arrow is replaced with Mario riding around in a vehicle from Mario Kart. On its blog, Google jokes, "Just remember to practice safe driving on the road--we don't encourage throwing bananas or red shells at other drivers in real life!"
This Mario companion won't be available for Mario Day alone: The feature will be in place for a week, though Google doesn't cite exactly when you can expect it to disappear. As noted above, it's hidden fun tidbits in the app before, such as being able to play Pac-Man on Google Maps.
Mario Day is a celebration of all things Mario. It takes place on March 10, much to my chagrin, due to that date being truncated to "MAR10." New My Nintendo rewards are already in place to commemorate the occasion, letting you get discounts on various games in the franchise across 3DS and Wii U.