It is back.  Production was legalized in the US in 2007 after being banned for nearly a century based on bogus claims of psychedelic properties.  The marquee ingredient in absinthe is wormwood but it typically includes other herbs such as anise and fennel.  Out of the bottle it is clear, but the spirit is prepared by dropping in a cube of sugar which then drives the herb particulates out of solution producing the famous green haze.  It is usually then diluted with 3 to 5 parts water but it is also a key ingredient in some cocktails.  The most famous is the Sazerac, a classic from New Orleans.

The last time I was in New Orleans, absinthe was not yet widely marketed and the Sazerac was still being made with the substitute spirit Herbsaint.  Did you ever notice that Herbsaint is nearly an anagram for Absinthe?  I don’t think its a coincidence.  But I think they missed a big chance with Thesbian.  Like Herbsaint, its not a word (clearly it should be) but its an exact anagram.

Here is a recipe for a sazerac from wikipedia:

One old fashioned glass is packed with ice. In a second old fashioned glass, a sugar cube and 3 dashes of Peychaud’s Bitters are muddled. The Rye Whiskey is then added to the sugar/Bitters mixture. The ice is emptied from the first old fashioned glass and the Absinthe is poured into the glass and swirled to coat the sides of the glass. Any excess Absinthe is discarded. The Rye-Sugar-Bitters mixture is then poured into the Absinthe coated glass and the glass is garnished with a lemon peel.

Here is Gary Vaynerchuck tasting and reviewing three absinthe brands.