This site is actually really interesting:
http://www.energyfiend.com/death-by-caffeine/You pick a drink from the enormous selection that's available, enter in your weight, and then it will tell you how many cans it will take to kill you by overdosing on caffeine. Just 223 cans of Mountain Dew to make me fall over in my grave.
Although it doesn't actually say how fast you would have to drink all of them.
