‘FERRIS’ WHEELING

When viewers get to the end of “Ferris Bueller’s Day Off,” they get a surprise: a trailer for John Hughes’ next movie, “Some Kind of Wonderful,” which only began production Aug. 11. The 90-second trailer also will appear on the Hughes’ “Pretty in Pink” videocassette (due in stores Oct. 1)--possibly the first time a coming attraction of an uncompleted film has appeared on a cassette.

“I think the video market for my films is the same audience that sees my movies in theaters,” Hughes told us. “They see the movies as being part of a series, so it makes sense to use one of them to advertise the other.”

And you can expect to see a trailer for Hughes’ “She’s Having a Baby”--now in pre -production--on the “Ferris” cassette when it hits the stores.

By the way, Hughes, who usually details the terrible troubles of teen-agers in his movies (and usually set in his native Chicago), may be coming of age in “Baby.” Kevin Bacon and Elizabeth McGovern get married, then discover the joys of parenthood. It’ll shoot later this month . . . in Chicago.