Sorry to burst your bubble folks, but that whole 'we only use 10 percent of our brains' jibber jabber is a myth. It had a place in popular folklore, and was even attributed to Albert Einstein, but the truth is, it's no truer than the last excuse you used to skip work.
That being said however, the field of human enhancement has seen some staggering progress, and some of it comes in a drug called Modafinil.
Modafinil, sold in pill form in India as Modalert, is basically a wakefulness-promoting agent (or eugeroic) which means it specifically improves wakefulness and alertness. It's used in the treatment of disorders such as narcolepsy, shift work sleep disorder, and excessive daytime sleepiness associated with obstructive sleep apnea. Basically, it wakes you the fuck up, and also helps you complete whichever task you decide to undertake with complete clarity and focus, without any of the jitters or side effects of drugs with similar effects, such as Adderall (amphetamine), or if you're a real tweaker - meth (I kid, I kid!).
We don't really know whether it was marketed as a Limitless-style drug or not, but over time, that's the persona that it's adopted, for better or for worse. Meant for the treatment of the above-mentioned disorders, it's actually being used by a far larger demographic - college kids, cramming last minute and trying to defeat that most dreadful of enemies, sleep (it needs a prescription, so please don't go around just trying to buy some). While that might make it sound like an underground party popper, it's actually also been cleared for use by soldiers of various militaries around the world for its fatigue-defeating and cognitive-enhancing properties, including the Indian military.
The whole hullabaloo over this miracle medicine is mostly because it seems very close to a drug of a different variety, but it isn't. There's no euphoria, there's almost no risk of addiction or dependence of any kind, and thanks to a very specific kind of coverage, it occupies a space in public opinion somewhere between a scheduled stimulant and a daily vitamin, but honestly, it's just another medicine with no magic properties.
At the end of the day, modafinil might sound like a sweet deal, and it probably does a lot of good for a lot of people, but it ain't no NZT-48, not by a long freakin' shot.
Please note: It's not advisable to take any form of unknown medication without consulting a doctor first.