"By LYNN ELBER, AP Television Writer Lynn Elber, Ap Television Writer – 13 mins ago LOS ANGELES – Jimmy Kimmel stepped into NBC's late-night fray on Jay Leno's turf, taking comic aim at him and NBC on "The Jay Leno Show." Appearing by satellite Thursday for Leno's "Ten at Ten" question-and-answer segment, the ABC late-night host was asked to relate his best prank ever. Kimmel replied that he told a guy five years ago that he'd give him his show, and "then I took it back." It was a thinly veiled reference to Leno's agreement in 2004 to surrender "The Tonight Show" to O'Brien in 2009, after 17 years as host. NBC, which is ending Leno's prime-time show, wants to return him to 11:30 p.m. EST by bumping O'Brien and "Tonight" to midnight, a plan O'Brien has rejected. The network was in talks with both hosts. Kimmel also joked that Leno had "$800 million, for God's sake," and advised him to leave other hosts' shows alone. Leno might have known what to expect from his guest, who'd already made pointed fun of him on Tuesday's "Jimmy Kimmel Live." Wearing an exaggerated fake chin to play Leno, Kimmel joked that he was taking over all late-night shows, including Kimmel's, and announced that ABC stands for "Always Bump Conan." O'Brien did some pummeling of his own Thursday, in what is becoming a pattern for him and Leno. "Hi, I'm Conan O'Brien, NBC's `Employee of the Month,'" he said in his monologue. "There's a rumor that NBC is so upset with me, they want to keep me off the air for 3 years. My response to that is, if NBC doesn't want people to see me, just leave me on NBC." Leno delivered a punch in his monologue: "Welcome to the new show, `I'm a Celebrity, Get Me Off NBC!'" he said. Meanwhile, NBC looked to the future by announcing that new and veteran NBC dramas and a comedy produced by Jerry Seinfeld will take over the bulk of the prime-time slots soon to be vacated by Jay Leno....."