Crack cocaine, also known simply as crack, is a free base form of cocaine that can be smoked. Crack offers a short but intense high to smokers. Crack cocaine is commonly used as a recreational drug.
Brain crack is a free base form of thinking. The intense high is delivered from idea to the brain. It offers an intense high to users. It is also known in it's more milder from called daydreaming. It is comonly used as a recreational drug. But brain crack requires a bit more effort on the users part.
For example, if you're a writer, you generally won't get high when thinking of a character putting on shoes. However, if you imagine those shoes are sparkly and red and respond to the voice command, "There is no place like home," then you're on brain crack. Hence the Wizard of Oz in it's entirety. The writer was high.
But brain crack isn't limited to writers, though they are big time users, but other fields as well. For example, what happens when you put a gyroscope in a scooter and add a really big cell phone battery? And then you convince people to call the invention "It" until it is revealed. You get a Segway, aka mass use of brain crack.
Brain crack has many positive side effects, mostly being, creativity and out of the box thinking. Nonetheless it is also responsible for fantasizing about how "great this is going to be" and sleepless nights as the user tosses and turns with excitement for the next day-- which inevitably sucks thanks to sleep deprivation.
Thus, users of brain crack must be careful. Otherwise they will be sleepy and unable to break the cycle between thinking up awesome idea and thinking about how awesome it will be when it's brought fruition, long enough enough to bring said idea to fruition.
This is also known by the very technical term, Brain Crack Catch 22.