tf o c.. ..l<: .... o > ~ a.> z By MICHAEl GIL TZ NOone has ever suc cessfully pulled a practical joke on actor William Shatner. "I'm too egotistical to think I would fall for any thing like that> says Shat \~r, whose sense of humor has kept him afloat in Hollywood for 40 years. "So it hasn't been done.</p><p> But I'm a con man and you know what they say about con men.</p><p> They can be conned more easily than anyone. ''I'm preparing myself for that. terrible moment when something is pulled on me." It'll have to wait.</p><p> Shat ner is the one pulling the strings when he plays a doozey of a prank on Riv erside, Iowa, the self-pro claimed, future birth place of Captain James T.</p><p> Kirk of "Star Trek." Next Tuesday, he launches a reality minise ries called "Invasion: Iowa" for Spike TV.</p><p> Over four nights -end ing April Fool's Day -we see Shatner and crew come to town pretending to shoot a low-budget sci fi movie.</p><p> But really they spend their time pushing the locals' buttons.</p><p> Think of it as "Candid Camera" with (really bad) special effects.</p><p> Shatner is the self-ab sorbed star -grabbing food off people's plates in the local diner (no one ever complains), walking around with his Emmy in hand, playing with the bust of Captain Kirk in the town square and asking the local minister if he minds if the movie people smash the lOO-year-old stained glass windows in the church.</p><p> Locals are recruited to act in the film and serve as go-fers, card holders and so on.</p><p> His cell phone goes off, blasting out - of all things - Usher's hit single "Caught Up" as the ring tone.</p><p> That gives them a front row seat to watch as Shat ner's body double spends ages stretching before his nude scenes or to over hear that Shatner's hap less personal assistant is "actually" his illegitimate son -but doesn't know it.</p><p> Still, no matter how goofy he acts, it's clear the townspeople -who bake the crew pies and put up with their idiocy with good-nature -are really thrilled about the movie.</p><p> When one local who wants to be a stand-up comic speaks movingly about how much this means to him, Shatner and the rest start to look very uneasy about the joke they're playing. (The townspeople find out the truth during the finale.) "It occurred certainly to me and to all of us that what we were about to do could be very cruel," says Shatner. "But if we played the joke on ourselves so that we appeared the fool and they reacted to our foolishness and Holly wood behavior, then it worked." His cell phone goes off during the interview, blasting out -of all things -Usher's hit sin gle "Caught Up" as the ring tone. "I need a loud ring," explains Shatner. "Somehow my upper reg ister is leaving me so I gotta get a lot of volume." It's a reminder that Shatner -who turns 74 tomorrow -has never been hipper.</p><p> His new movie, "Miss Congeniality 2," opens on Friday.</p><p> And of course, he's rev elling in his "Boston Legal" role -Denny Crane.</p><p> The show has en joyed a constant stream of guest stars. "Heather Locklear is in my arms -not as we speak, but shortly after 1 put the phone down," says Shatner about his "T.J.</p><p> Hooker" co-star who will be two upcom ing episodes in May.</p><p> That has to be more fun than another recent guest, Carl Reiner, right? "I put him in my arms, too," says Shatner. "I have no discernment what soever."