By Margaret Lyons
August 21, 2009 at 04:09 PM EDT

Big Brother‘s watching — sporadically, at least: CBS’s summer staple has been all over the ratings map the past few weeks, with viewership as high as 9 million on Sunday and as low as 6.7 million earlier this month. Who Wants to be a Millionaire pulled in a respectable 6.8 million viewers, picking up half a million in its second half hour, mostly from Big Brother. Fox’s NFL preseason game held steady over the course of the evening and brought in the most of the viewers in the 18-49 demo, but CBS owned the night, with its 10 p.m. rerun beating NBC and ABC combined.

Time Show Viewers (in millions)
8:00 p.m. Big Brother 11 (CBS)

Who Wants To Be a Millionaire (ABC)

Fox NFL Pre-season Game (Fox)

30 Rock (NBC)

Supernatural (The CW)




3.3 (repeat)


8:30 p.m. Parks and Recreation (NBC) 2.5 (repeat)
9:00 p.m. CSI (CBS)

Grey’s Anatomy (ABC)

The Office (NBC)

Supernatural (The CW)

7.8 (repeat)

3.5 (repeat)

3.4 (repeat)

2.0 (repeat)

9:30 p.m. 30 Rock (NBC) 3.0 (repeat)
10:00 p.m. The Mentalist (CBS)

Law & Order (NBC)

Private Practice (ABC)

7.6 (repeat)

4.0 (repeat)

2.1 (repeat)