Remember victorious Will, rapper Mike, and that knife-wielding Justin? Don’t worry, neither do we. But exec producer Arnold Shapiro is convinced that America will return for yet another season of CBS’ ”Big Brother” (the show debuts in early July). ”Judging by the ratings of ”Survivor: Marquesas” and ”The Bachelor,” the appetite for reality programs is stronger than ever,” Shapiro says. The number of applicants certainly bears that out: More than 5,000 people clamored to have their every move televised, up from 3,500 last year (Shapiro is currently screening 50 semifinalists in L.A. before narrowing them down to the 12 housemates). He promises big changes in season three: The house decor gets a makeover, background checks will be more thorough, and there’ll be a better policy on informing the shut-ins about major world-news events (last year the houseguests never got a sense of the seriousness of the 9/11 attacks, and as Shapiro notes, ”The government keeps telling us another terrorist action is probable”). One other big switcheroo: ”We’re going to include some twists that will make the houseguests rethink their preconceived strategies.” Oooohhh, how ”Survivor” of you.