Caffeine powder is pretty interesting. In college, my roommates and I stored half a kilo of anhydrous white powder in a closet. It's incredibly versatile: you can mix it into drinks or food, put it under your tongue, and even insufflate it (higher bioavailability, shorter duration).

You have to be careful with it though, because like the article says, it doesn't take much to kill a person. Usually when you order caffeine powder it comes with a little 50mg scoop so you can track consumption.