'The Best Week Ever' has chosen its list of "Top Ten Sitcom Cameos Made By Other Sitcom Characters".
To be sure, it's a flawed list; they don't even like half the choices they made. But at least they provide videos to go with their choices, some of which might be considered rare.
In their comments section, I clued them in to the "Las Vegas" themed night of ABC programming, in which characters from 'Coach', 'Ellen', 'Grace Under Fire' and 'The Drew Carey Show' all ran into each other while in Vegas. (My blog-buddy Thom Holbrook has the details on that.) And the big star of that night was Luther Van Dam (Jerry Van Dyke) of 'Coach', who was the only one to appear on all four shows.
He was inducted into the TV Crossover Hall of Fame for making four appearances in one night....
(Pictured above: Spence Novak and Paige Clarke of 'Ellen', the eponymous star of 'The Drew Carey Show', and Luther Van Dam of 'Coach'.)