ON AND OFF THE AIR:
* Take a melodic time-travel trip tonight on Maryland Public Television, with a pair of documentaries on influential pop music groups.
At 10 p.m., lead singer Justin Hayward narrates "Moody Blues: Legend of a Band," a history of the group's 20 performing years, which includes 24 songs.
And at 11:30, "The Story of the Mamas & The Papas" offers the local angle provided by the late "Mama" Cass Elliott, who hailed from Baltimore and, at the height of the group's popularity, received a home-town ceremonial procession.
The 90-minute documentary includes comments from Dick Cavett, Joe Cocker, Mick Fleetwood and Glenn Campbell.
* WBFF-Channel 45 has announced it is accepting entries for its fifth annual "Champions of Courage" essay contest, in connection with Black History Month (February). Open to city public school students in grades six to 12, the contest asks for short writings on a personal hero whose life exemplifies the teachings of Dr. Martin Luther King Jr.
Twenty-eight finalists will be chosen to read their essays in public-service spots to air on Channel 45 in February. The deadline is Jan. 10. For information, call 467-4545.
And regarding another public service program at Channel 45, the station has won a first-place national media award from Mothers Against Drunk Driving. The citation honored the station's annual Operation Prom campaign, in which students and parents contract to be alcohol-free through the spring prom period.
* Due to erroneous information from the station, the date of Mayor Kurt L. Schmoke's two-hour guest appearance on Tyrone Parker's Sunday talk show on WCBM-AM 680 was wrong in last Friday's Media Monitor. The mayor was not on last weekend, but is scheduled this coming Sunday, at 8 p.m.
* Speaking of the mayor, he is scheduled to participate this week in a live televised debate with Republican challenger Samuel Culotta. It is at 8 p.m. Friday on WMAR-Channel 2, and MPT will repeat the debate at 9:30 a.m. on Saturday.
* Whew! The turnaround time on commercial videotape marketing is getting shorter and shorter.
How short? Well, with Game 3 of the World Series due tonight (at 8 p.m., Channel 11), Turner Home Entertainment has announced the production of "The Atlanta Braves, '91: The Miracle Season," a highlights video.
The video arm of cable mogul Ted Turner (who is also owner of the Braves, of course) says the cassette documenting the team's last-to-first climb will be available three weeks after the Braves' last game -- whenever that will be. The team trails the Minnesota Twins two games to none.
The Turner video team was pretty quick, too, on "The New Russian Revolution," a recently available compilation of CNN news coverage of the August upheaval in the Soviet Union.