For me it was The Ecstasy Club by Douglas Rushkoff. When I read it I thought it was amazing and transcendent and when I read it again about 10 years later I felt quite the opposite. On the other hand Senor Vivo and the Coca Lord by Louis de Bernières is still one of my favorite books 15 years after reading it for the first time.
I went into one of these in the New Museum in NY it was incredible. I would do it again but maybe not paying money for it.