I had a mad idea about making wine from wormwood, and distilling it. But a wee bit of googling revealed that absinthe is actually made by mascerating the wormwood and other herbs in alcohol, and the distilling it again, and then mascerating more herbs. (Never mind absinthe, and miss out the distillation bit, just making tinctures from cheap vodka and any number and combination of herbs sounds like a lot of fun).
A wikipedia article seems to suggest that the thujon levels of James-Joyce-in-Paris era absinthe were not necessarily that high. (I remember reading somewhere a theory that Joyce got some of his inspiration for Finnegans Wake through absinthe enhanced dream recall). This study (the abstract anyway, I'd like to see the whole study and see what the "other mood state dimensions examined"are; I do miss my Athens account this weather), shows an effect on attention. I once smoked sage, which also contains thujon, without any noticeable effect.
I pinched this wonderful picture from here, which is a very interesting article, GABA GABA hey.