I found itstrange that at least a few people here talk about Soft Machine, Caravan, and Hatfield and the North, but no one appears to have heard of Egg. they've got a great keyboard player(Dave Stewart, who later plays in Hatfield and the North) and bassist(Mont Campbell).
heres some stuff(audio only, because there isnt any live footage of them, sadly....)
YouTube - Egg - Enneagram
YouTube - Egg - A Visit To Newport Hospital
YouTube - Egg - Long Piece No. 3: Part Two
YouTube - Egg - Germ Patrol
Also, as an interesting note, the amazing steve hillage was a member on guitar, but left before they recorded their first album.