No, you aren't seeing double. Both Fox and NBC really are running the same shows twice a week, sometimes even thrice. The reason: February sweeps. To boost viewership during this all-important ratings month, the third- and fourth-place networks are temporarily replacing weaker series (A Different World on NBC; The Edge and Likely Suspects on Fox) with repeats and special episodes of higher-rated shows. ''It's a pretty effective way of punching up a time period on a short-term basis,'' says Dan McDermott, a senior vice president at Fox. ''You just have to be careful not to overexpose the shows by running them too often.'' How often is too often? You decide.
*Fox has been airing In Living Color twice a week since December, with new episodes on Sundays at 8 p.m. and an older rerun on Thursdays at 9 p.m.; on Feb. 4 and 11, the network added another Thursday rerun at 9:30 p.m.
*Fox's Cops has long aired two episodes each week, on Saturdays at 8 and 8:30 p.m. On Feb. 21, an additional hour-long special will air at 10 p.m., so that fans can relish the equivalent of four Cops episodes in one week.
*On Feb. 4, NBC started serving two rounds of Cheers every Thursday night, a rerun at 8 p.m. and a new episode at 9 p.m.
*A special hour-long, all-Mafia episode of Fox's America's Most Wanted will air on Feb. 27 at 9 p.m., in addition to the show's regular hour on Friday at 8 p.m.
*Sightings, Fox's ghost and flying saucer ''reality'' series, will be airing twice on Fridays, at 9 and 9:30 p.m.