On this day in musical history a 19 year old lad Scott Haplin took over the drum stool from Keith Moon after he had his drink spiked with a horse tranquiliser!! Moon had collapsed twice before Pete Townshend put out a request for a drummer and up stepped Scott Halpin who had turned up at the show with no ticket but had bought one off a scalper.
This happened at The Cow Palace in San Francisco on this day in 1973.
Here's a great BBC Radio 4 documentary about the whole night.
Video of the show. Shot in Black and White and although not great quality it's worth a watch.