While Steve Reich is not directly related to generative art, I think he somehow fits the overall theme of this blog. Even though his minimalistic phrases phasing in and out of sync easily could be performed by a computer, for a human the rhythmic skills necessary to perform his compositions are beyond imagination.
‘Piano Phase’ was originally composed for two pianos (and two piano players). Here both parts are performed by Peter Aidu, a Russian composer and piano player.
Another (only vaguely related) keyboard video:
Sun Ra Keyboard Solo (1980)