Joe Boyd, in his book White Bicycles, relates how the Incredible String Band didn't play their slot at Woodstock because it was raining - they were using electric instruments by then. The slot was taken by Melanie who performed - in the rain - to some acclaim. This apparantly inspired 'Candles in the Rain'.

And she made it into the film of Woodstock, whereas ISB - who performed next day among rock groups - didn't.