He only played with the band for about seven years, but Ron McKernan, or Pigpen, was the frontman of the Grateful Dead in its early days, and was responsible for a lot of the band’s hard R&B sound.
(Photo from Dead.net.)
Whether it was Turn On Your Love Light, Good Lovin’, Smokestack Lightnin’, or In the Midnight Hour, Pigpen’s long, improvised raps were high points of early Grateful Dead shows.
Pig drank too much, and died from it, but he’s remembered in lots of recordings, especially those in 1969-1971. He would have been 70 years old today.