Thursday ratings: O'Brien vs. Letterman; ABC wins

The late-night teeter-totter shifts again ...

CBS' "Late Show With David Letterman" (3.5 household rating) outdrew NBC's "Tonight Show With Conan O’Brien" (3.0) in the overnight household ratings.

While NBC, weary of getting headlines based on a measurement that’s not their sales focus, has dug up overnight demo numbers from 21 local stations ahead of next week's late-night nationals. The network says the numbers should be fairly accurate: O’Brien (1.5 adults 18-49 rating) dominated Letterman (0.9), albeit by a slimmer percentage than last week. 

In primetime:

ABC won Thursday with Game 4 of the NBA Finals (12.2 million viewers, 4.8 preliminary adults 18-49 rating), Fox was second, leading with "So You Think You Can Dance" (8.7 million, 3.2). CBS was third with repeats. NBC fourth with "I'm a Celebrity Get Me Out of Here" (5.1 million, 1.8), now Heidi and Spencer free, dropping slightly from last week. NBC also had repeats and "Listener" (4.4 million, 1.3).