Norm Crosby's Comedy Shop with guest Michael Keaton (1978)

It can be a serious mistake for a comedian to accept an invitation for a television appearance before they're ready - when their material is still shaky and not fully polished. Michael Keaton makes just such a mistake with this, his first stand-up appearance on American television (he had previously performed stand-up on the Canadian CTV Network on The Alan Hamel Show). It wasn't his American television debut however - that had occurred a couple years earlier on an episode of Mister Rogers' Neighborhood.