George Orwell’s “Big Brother Is Watching You” warning may sometimes ring true, but the reverse did not on Saturday night as the second episode of Big Brother 2 failed to attract ratings that were any larger than those for a mediocre summer rerun. The show’s 3.6 rating and 8 share in the 8 p.m. hour was identical to the numbers for a repeat of Walker, Texas Ranger a week earlier. (In fact, aside from a rerun of Cops on Fox, the show produced the worst ratings for any primetime show airing Saturday night.) By contrast, NASCAR racing on NBC proved to be a smash as it produced a roaring (for a summer Saturday) 5.9/12 in the 8 p.m. hour, then went on to finish with a 7.2/14 in its final half hour at 10:30 p.m. Earlier in the day, the Big Brother Web site showed five contestants naked in a hot tub, licking whipped cream off one another. The steamy goings-on were presented on the last day that the Web site was available for free. It now costs $19.95 to access it for the three-month run.