Its described as a "blackout in a can" or "legalized liquid cocaine"...

After 23 students were hospitalized for alcohol intoxication at the beginning of the Fall semester, Ramapo College in Mahwah, New Jersey banned all alcoholic energy drinks on campus. While all brands of alcoholic energy drinks are banned, one brand in particular, Four Loko, was called out by name. The drink, which comes in 23.5 oz cans, in flavors like Fruit Punch, Blue Raspberry, and Cranberry Lemonade, is cheap (about $2.50 each) and has an alcohol content of 12%. Consuming a whole can of Four Loko apparently produces the same effect as drinking three beers, a can of Red Bull, and a shot of espresso.

Source: Consumer Affairs