Of course there's the scene at the studio where the Jaws shark appears and Columbo asks if that's the shark from the movie.

Grant said:

"There's Army Archerd playing himself, something that almost never happened on COLUMBO (which I'm glad about, since that idea gets out of hand on most shows)."

Nice observation, and one I'd have liked to agree with, except it happened just enough to provide a lot of annoying memories. Several awkward moments that come to mind:

In "The Most Crucial Game", there was a couple of minutes of "fill" with some basketball players shooting hoops (including a very young and non-greased-down Pat Riley). Edith Head appeared in "Requiem for a Fallen Star", and seemed to have trouble not tripping over Anne Baxter's lines. And perhaps the most annoying was the group of poker-playing has-beens in "Uneasy Lies the Crown".

And who can forget Little Richard in "Murder of a Rock Star?"

I can't help agreeing with those (except that I think Edith Head was at least worked into that scene A LITTLE "smoothly").

One comical thing in my case when it comes to that basketball scene is that I immediately recognize one of the names from being an OUTER LIMITS fan as opposed to a basketball fan, because Leroy Ellis played an eight foot tall space creature in an Outer Limits episode!