According to Wikipedia, "real" absinthe is legal throughout the European Union, as well as a number of other countries (Australia), though France prohibits the sale. The US is not one of those. That's quite different to the dozens of different variations of "it's illegal in every country except X and Y" I've heard from different people over the years. There seems to be a great deal of confusion between traditional absinthe, which contains thujone, and high-proof tourist booze, which does not. The Wikipedia article is muddy on this as well.

When it was first outlawed in France, Pernod moved their production to Barcelona. Though it closed down in the 60s, there are still several small producers in the area making "artisanal" absentas.

The best, and quite possibly only, authentic place to take absinthe with all the associated ritual and atmosphere is Bar Marsella, in the Raval area of Barcelona. It's an absinthe bar that opened in 1820, hasn't been decorated since then, and comes complete with all the spoons and assorted glasswear (and sugar, if you must, but a true afficionado would never do such a thing!). Wilde, Picasso and Rimbaud have all partaken here, it's said. It was better before it made the Lonely Planet guide and all the backpackers showed up, though the neighborhood is scary enough that I suspect many of them turn back before they find the place.

I can attest from personal experience that the real stuff does pack a whallop, though I don't know if I'd say it's particularly hallucinogenic. It's absolutely a different kind of drunk, though, than your more run-of-the-mill alcohol. Let's just say it involved several policemen and a lot of pepper spray.

"After the first glass you see things as you wish they were," Oscar Wilde once said of absinthe. "After the second, you see things as they are not. Finally you see things as they really are, and that is the most horrible thing in the world."