Keith Richards wrote the famous riff from ’(I Can’t Get No) Satisfaction’ in a dream and recorded it in his sleep.
“I go to bed as usual with my guitar, and I wake up the next morning, and I see that the tape is run to the very end. And I think, ‘Well, I didn’t do anything. Maybe I hit a button when I was asleep.’ So I put it back to the beginning and pushed play and there, in some sort of ghostly version, is [the opening lines to 'Satisfaction’]. It was a whole verse of it. And after that, there’s 40 minutes of me snoring. But there’s the song in its embryo, and I actually dreamt the damned thing."