CBS Challenges NBC in Thursday Comedy Sweepstakes

LOS ANGELES - One of the most anticipated ratings battles of the new television season begins Thursday when CBS fires a "Big Bang" in a bid to gain a comedy-block foothold in NBC territory.

TV's top-rated comedy "The Big Bang Theory" will face NBC's "Community," and the new Twitter-inspired sitcom "$#*! My Dad Says" goes up against Emmy favorite "30 Rock." The two geek-friendly CBS shows could be dubbed "Must-Tweet TV."

There's seldom been more curiosity about a fight whose winner seemed almost certain. The question isn't whether CBS will win the 8 p.m. hour, but by how much -- and how its presence will affect NBC.

If CBS' plan succeeds, the network eventually could shift "CSI" out of the 9 p.m. anchor slot -- just like it has with the rest of its "CSI" spinoffs -- and set up a two-hour comedy block on TV's most lucrative night for advertising revenue. (Film studios use Thursday spots to target weekend moviegoers.)

NBC isn't going down easy. "Community" has fandom-favorite Betty White as a guest star for its premiere. The network is also airing a pre-telecast "Twittersode," an 80-tweet scene acted out on the Twitter feeds devoted to the show's characters, just before airtime.