First, a word or two about absinthe. Or some questions and answers. Is it illegal? No, at least not in the form you're likely to find it. The "active" ingredient (other than alcohol) is classified in the United States as a "controlled substance" but only in higher quantities than are generally available.
So, what is the stuff, specifically? Absinthe is classified as a "spirit", a distilled alcoholic beverage not bottled with added sugar (which would make it a liqueur). Absinthe belongs roughly in the same category as scotch. Derived from wormwood, absinthe typically has a very high "proof", anywhere from 45 to 75 percent.
Is that why it has such a reputation? Only partially. The herbal concoctions used to make absinthe (and there are many recipes) include natural stimulants as well as natural sedatives. Combined, the effect is interesting. Rather than slovenly drunkenness, one experiences a kind of heightened awareness. In other words, absinthe was the Victorian equivalent of acid. Of course, regulations in those days regarding food purity were lax at best. A bottle purchased in 1890, for example, might well contain cocaine.
Ritual surrounds absinthe, almost as if the drinking of it were an act of the occult. They used to say that a green fairy lived in the absinthe, and that to drink it was to let such a creature into your very soul. Take a glass, ideally, one designed specifically for the experience. A somewhat tall brandy glass will work. Pour a finger or two of absinthe into said glass. Now, place the absinthe spoon atop your glass. If you don't have one, a carefully balanced fork will do. However, a Spork will not. Place at least one (or two, or even three--it depends on taste) cubes of sugar upon your fork or spoon. Now pour ice water over the sugar into the glass. Not all at once, it takes time. As the sugar dissolves, the drink changes color and green turns into a milky white. The name for this is the "leche." (There are other color absinthes, including red.)
Now drink it. And enjoy. You'll find it tastes something like anise, or maybe licorice. Personally, what I look for in a glass of absinthe is "smoothness."
For the record, you can prepare it other ways. In Bar Sinister, a "goth" bar in Hollywood, they'll put ice and absinthe and sugar cubes in a shot glass then shake it like a martini. They also will mix it with fruit juices (try the "red fairy" if you go--it is delicious). But don't do what Johnny Depp did in From Hell. Putting an open flame near high-proof alcohol is not a good idea. Quite apart from the fact, burned sugar tastes nasty, the alcoholic content gets burned away!
Temperance leaders made a lot about the mystique of absinthe. One story from Switzerland made the rounds around the turn of the twentieth century involving a day laborer. Details vary but the essence goes something like this. Said day laborer got up one day and drank a bottle of wine with breakfast. At work, he drank another bottle of wine, had some beers with lunch, yet another bottle of wine then headed to the local pub with friends. Some brandy, more beer and more wine were capped off with one glass of absinthe. He then went home to murder his family with an axe. Naturally enough, people looked at these events and made the logical deduction; they blamed the absinthe. Over time they managed to get absinthe banned, the first victory in the war for Prohibition. Honestly, they had a point. In the 1800s, everyone knew drinking water was often dangerous (and they were right). Most folks quenched their thirst with gin, with little or no awareness of what we today call alcoholism. What followed Prohibition's enactment--the upsurge of organized crime, rampant corruption, machine gun massacres--might be viewed as an example of how linear thinking doesn't always work. One is tempted to suggest the leaders of the Temperance Movement might have enjoyed greater long-term success by drinking some absinthe and considered the problem from a state of altered consciousness.