The 'Oo, and perhaps their finest studio effort.
Found this on YouTube the other day and a) I'd never seen it before and b) it's like the coolest thing ever. Actually, it may in fact be the official video for the song (although the '60s term was promo film, of course).
It is perhaps also worth noting -- according to no less an authority than the song's composer Pete Townshend -- that drummer Keith Moon went to his grave having absolutely no memory whatsoever of the session at which the song was recorded.
An indication, as Pete told Rolling Stone, of Moon's "state of mind at the time."