To play the game you just have to visit Maps website and click on the little Pac-Man icon on the bottom-left of the screen where you typically switch between Satellite and Map backgrounds of the map. When you do so, Google will transform street grid in your area into a Pac-Man level. To navigate you need to use arrows on your keyboard. You’ll also hear the Pac-Man music theme which will definitely remind you your childhood. Awesome:)
But be fast this feature will most likely disappear in the next 24h.