Originally posted by: Dunbar
On Mythbusters they bought powdered (highly concentrated) caffiene to test the Mentos fizz bomb myth. They said it hard to get because if you took enough it could kill you. I'm guessing death by caffiene would not be a pleasant experience.
you can buy it on ebay, legally, as it's not a controlled substance.

when I searched on ebay awhile back, you could get bottles ranging from 1/2 oz (14g) to 2oz (56g). Taking half of the smallest bottle is a potentially fatal dose.
Caffeine has its best effects around 1g, at least, how I'd feel.. any more than that and I've felt sick and not really enjoying the experience (and that's roughly 1g from espresso and assorted caffeinated candies, and cans of Monster, over the course of a few hours). You get a euphoric feeling towards the late morning (I consumed this kind of caffeine usually once a week, for fun, during high school. yes, i thoroughly abused caffeine for fun), the entire morning and into early afternoon you have bountiful energy and feel like you can accomplish anything.. but the euphoric feeling is actually the bridge between a lot of energy, and an insane lack of energy. The crash is insane, and the feeling that accompanies the crash is one that is just, hard to describe but I don't recommend it. Now, I don't really ever approach that kind of caffeine consumption, but I'll have a couple cups of coffee, or an energy drink, or a caffeine pill... something to perk me on a very long day. Last quarter I had quite a few long days, and those days, coming off a night of 3 or 4 hours of sleep (typical for a school night, all week long)... caffeine became a wonderful companion and often needed to top-off with something in between my two later classes on those long days. i came home and sometimes just crashed.