Once again, the fast nationals for last night have to be taken with a grain of salt as some ABC, CBS, and NBC stations preempted network programming for NFL coverage, leading to possible ratings inflation. With that in mind, CBS’ Big Brother, which featured double elimination, posted its largest audience (8.5 million) and matched its best 18-49 rating (3.2/9) this season, up 10% in the demo from last week. CBS easily won the night with the three highest-rated programs — Big Brother and two repeats, comedies The Big Bang Theory (2.1/7) and Rules of Engagement (1.8/6), which beat ABC’s original Wipeout (1.9/6, flat vs. last week) in the 8 PM hour. At 9 PM, the finale of ABC’s Expedition: Impossible (1.5/4) was up 15%, while Rookie Blue (1.3/4) at 10 PM was up 8%. NBC and Fox aired reruns.