'Are You Being Served?'-virtually every episode, but particularly 'German Week', 'The Hold-Up', and 'The Pop Star'.
'Cheers'-Cliff is a contestant on 'Jeopardy!'(also, during the last season, there was a St. Patrick's Day-themed episode, where Sam auditions an 'Irish band', expecting the usual 'upbeat' classics, and instead they play the darkest, most melancholy, dirgelike music..'Everywhere we looked, was death, death, DEATH!' ;D
'Night Court'-any episode guest-starring Mel Torme and/or John Astin, focused on Dan Fielding, or involving the gang having to hear a large backlog of cases in one night...sometimes, one episode met all three criteria!

'Cosby Show'...most episodes before season 4, and all before season 7.
'Gilligan's Island'-Phil Silvers as Harold Hecuba
'All in the Family'-anything prior to the Jeffersons 'movin' on up' to their own show, and Mike and Gloria 'movin' on out' of the Bunkers' house to live next door.
'The Dick Van Dyke Show'-the 'It May Look Like a Walnut' episode, with the alien Danny Thomas impersonator from the 'Twilo Zone'. ;D
'Happy Days'-'My Favorite Orkan', introducing Robin Williams as Mork(and, although most episodes after '79 or '80 aren't that good, the show still had its moments-another Phil Silvers guest shot here, around 1980, and a good turn by Tom Hanks during season 10, as a geek who vows 'vengeance' on Fonzie over a childhood incident)
'I Love Lucy'- 'Job Switching'.