Your teachers were right: Your brain is like a muscle. To make it smarter, all you need to do is lift intellectual weights -- and often. Studies show that regularly exercising our minds with challenging new stimuli -- not endless hours of  Keeping Up With the Kardashians  -- increases IQ. It’s true. When you learn something new, you grow your gray matter. It’s not rocket science. Sure, crossword puzzles and sudoku are brilliant ways to sharpen your intellect and  expand your neuroplasticity , but they’re far from the only options here. Other, less ho hum hobbies, like working out, for example, are also proven to spur your smarts. In fact, breaking a sweat improves not only your physique, but also your long-term memory and object recognition memory. Think about that next time you hit the gym. Believe it or not, playing video games is another fun, engaging way to boost your brainpower. I know. The hover mom in me didn’t want to believe it either. Despite their bad...