The City That Forgot About Christmas is a direct sequel to Christmas Is.. in that it features the same central characters, a young boy named Benji and his dog, a sheepdog named Waldo. I actually thought this came out some years later, but as I found the video from pressmin, I discovered that it was much sooner. Radio legend Casey Kasem voices Benji's dad, and also, as memory serves, did the voice-over narration for the commercials promoting both this show and Christmas Is.... and the 3rd Benji & Waldo special, Easter Is..... Here's a sample:
The cast also includes Sebastian Cabot (Family Affair), Louis Nye (ex-The Steve Allen Show) and Charles Nelson Reilly (The Ghost & Mrs. Muir and, later, Match Game). City has aired annually, initially in syndication, but more recently on cable on any religious-themed network, such as TBN or EWTN. It's too bad they don't make more specials like this.
However, I have not seen this in its entirety before, so I can't give a fair rating.