Google has already got April fools going and has given Google Maps users on both iOS and Android the ability to catch Pokemon.
To get started, you have to make sure you have the latest version of Google Maps. Then hit the search bar, wait for a moment and you'll see a new button that says "Press Start". Once you hit that, the map will automatically guide you to a different location.
You can now start moving around the map, catching as many Pokemon as possible. There are 150 to catch and you get a proper Pokedex, giving info on the Pokemon, its type, height and weight.