Ways to stimulate your Brain

Experience the third dimension - properly.
Birds are far more intelligent than their brain size should give them a right to be. Why? A myriad of reasons, and one of them is: Birds fly. We grounded folk live all to frequently in a world reduced to two dimensional plans of places. Rebel. Live in your birthright as a three dimensional creature.

Learn a new language.
Don't be hemmed in by the way your parents talk! Language is the soul of the human race, and divided we are far more diverse. A language is more than just a set of words: it is the life-blood of a culture. The English-speaking world is far more homogenous than it should be for its size. Europe is far less homogenous than it should be, for its size. Learn a language, learn a life.

Change your route.
Shake up this idle brain of yours! Give it a new set of sights and sounds and smells to deal with! Change your route: change the way you get from one place to another. If you drive, walk Or cycle. Maybe roller-blades are more your speed? Or go down that alley, turn left instead of going straight through... take the scenic route to your destination.

Sense something different.
As above, only in one place. Listen to weird music, find pictures of Aurora Polaris, burn incense, eat insects (clean!), feel petals and leaves and the bark of the largest tree you can find.... expand all your senses, for they are the gateway to your mind.