I remember back in my highschool days (as well as freshman and sophmore yrs of college), I would consume not only caffine drinks (MD, Coke, Pepsi, etc.), but I was also taking caffine pills (NoDoz, Vibrin (sp?), etc.). After a while, I got so used to the caffine levels, it stopped affecting me (the so-called "caffine tolerance"). After giving caffine up for a year or two, I'm back to consuming caffine like mad... I swear... Those 1 liter bottles of Code Red Mountain Dew just don't help us caffine ingesting folk... Oh well, at least I'll die awake... ^_~