The original incarnation of the game show What's My Line? was on TV from 1950 'til 1967. Many of those episodes are on YouTube and they get an awful lot of hits, especially (I suspect) from folks who just want to watch the Mystery Guest spots. A lot of the episodes are missing but every now and then, one turns up. The one for July 23, 1967 recently surfaced and I've decided to link you to it.
You have a choice: If you want to watch the entire half-hour, click here. If you just want to see the Mystery Guest spot — a particularly good one with Carl Reiner — then click below. I've set it to start at the point in that episode when he comes on…