And the one that sticks most in my mind was Black Box with Ride On Time. The whole family was watching it and I had to hide the fact that I had a stiffy watching the singer's boobs bouncing merrily on TV
https://www.youtube.com/watch?v=vTTMNIpOz50
Have to go some way to beat seeing Jocky Wilson on TOTP.
Edit - Damn! Beaten to it. Okay - 2 other memorable performances.
King Kurt's one and only performance when they chucked gunk and feathers at each other
https://www.youtube.com/watch?v=OS-1K_IDf60
and All About Eve having a sulk...