Halloween festivities took a toll on Monday’s top-rated series, as the likes of ”Two and a Half Men,” ”Dancing With the Stars” and ”House” hit season lows. One series that bucked the trend was ABC’s ”Castle,” which was on the rise in an hour that saw NBC newsmag ”Rock Center” open to low numbers.

Distractions surrounding Halloween contributed to lower viewing levels on the night, especially early. Nielsen estimates that the numbers of adults 18-49 watching television in the 8 o’clock hour on Monday was down 13% from the previous week and 11% from the same week last year.

According to preliminary, affiliate-based national estimates from Nielsen, CBS was the No. 1 broadcaster in demos Monday with its potent comedy lineup of ”How I Met Your Mother” (4.1/13 in 18-49, 10.7 million viewers overall), ”2 Broke Girls” (4.2/12 in 18-49, 11.1 million viewers overall), ”Two and a Half Men” (4.7/12 in 18-49, 13.8 million viewers overall) and ”Mike and Molly” (3.8/9 in 18-49, 11.5 million viewers overall). Though all at season lows, they remained the night’s top four entertainment series in 18-49. And at 10, ”Hawaii Five-0” dipped week to week but remained solid (2.9/8 in 18-49, 10.3 million viewers overall).

ABC, the night’s leader in total viewers, opened with the holiday special ”Scared Shrekless” (1.7/6 in 18-49, 8.7 million viewers overall), followed by the lowest rated performance episode to date of ”Dancing With the Stars” (2.8/7 in 18-49, 16.3 million viewers overall from 8:30 to 10 p.m.). Closing out the night, though, ”Castle” was on the upswing (2.9/7 in 18-49, 12.9 million viewers overall).

(Note that ratings for the early part of the evening for CBS are subject to revision as the net’s preliminary numbers include viewership in San Diego for the NFL game between the Chargers and Kansas City Chiefs, which didn’t wrap until after 9 p.m. in the West. Also, tweaks to ABC’s program averages are expected as the net’s Kansas City station aired the game.)

Elsewhere, Fox dramas ”Terra Nova” (2.1/6 in 18-49, 6.4 million viewers overall) and ”House” (2.5/6 in 18-49, 6.5 million viewers overall) were down 25% and 19%, respectively, from their most recent originals two weeks ago.

And at NBC, ”The Sing Off” (1.4/4 in 18-49, 4.4 million viewers overall) dipped to its lowest score of the fall, and was followed by the debut of ”Rock Center with Brian Williams” (1.0/3 in 18-49, 4.1 million viewers overall), which performed better than last week’s ”Prime Suspect” repeat but not as well as the average in the hour earlier this fall for ”The Playboy Club.”

CW aired two special off-night repeats of ”Ringer,” which combined for a 0.3/1 in 18-49 and about 900,000 viewers overall.

Preliminary 18-49 averages for the night: CBS, 3.8/10; ABC, 2.7/7; Fox, 2.3/6; Univision, 1.3/4; NBC, 1.2/3; CW, 0.3/1.

In total viewers: ABC, 13.9 million; CBS, 11.3 million; Fox, 6.5 million; NBC, 4.3 million; Univision, 3.0 million; CW, 0.9 million.