Nothing, apparently. It's back on, 40 years later.
The 14 Hour Technicolor Dream was an event staged in London on the 29th of April 1967 that was widely regarded as the first flowering of freakdom in the United Kingdom. Pink Floyd headlined; The Pretty Things and Arthur Brown also starred. I'm not sure I've ever read a good write up about it on teh intarwebs (even Wikipedia is terse on this one), but there's a fine write up in Mick Farren's Give the Anarchist a Cigarette, and a there's a few Pink Floyd pages which describe it.
For good or for ill, the ICA has decided to re-stage it on its 4oth anniversary. I have mixed feelings about a recreated be-in. I still have my Summer of Love 1988 T-shirt, and I'm not sure I'm ready for another 20th anniversary so soon. On the other hand, I'd love to see the movies that are promised. What a drawback to no longer living in London - I never thought all of them would be in the same place!
According to Hugh Dellar, one of the 40th anniversary organizers, quoted in the Independent, above: "The more I learned about it, the more interested I became because it contained all the elements of what had come before it and all the seeds for what would come after. In many ways it was the pinnacle of British youth culture. The people who were involved in it went on to be key figures in other areas."
I love the sixties and seventies, you know me. But if I were today's British youth culture (who he?) I'd be sorely tempted right about now to prove Hugh Dellar wrong about those seeds.