There was sad news on “Celebrity Rehab” and comic joy on the late-night shows over a newcomer on the campaign trail, but the top spot on this week’s Top Five has to go to Piers Morgan.

1) A watershed moment for “Piers Morgan Tonight”: Opinions might vary on this, but we happen to think Christine O’Donnell made a fool of herself when she objected to perfectly reasonable questioning and then walked off of Morgan’s CNN talk show this week. In her insistence that Morgan only ask questions that would be useful in promoting her book, she came across like a clueless 10 year-old. As for Piers, he handled the situation, well, like a grown-up.

2) The joke’s on Rick Perry: Texas Gov. Rick Perry’s arrival in the presidential campaign (as a Republican, in case you didn’t know) was a hot topic for the late-night shows — what was left of them this week, that is (Jay, Dave, Craig Ferguson and Jimmy Fallon were all off, and “Lopez Tonight” was gone). But of the ones who were left, we liked Stephen Colbert’s approach on the Wednesday edition of “The Colbert Report” on Comedy Central.

3) Sad tribute to one of their own: On this week’s “Celebrity Rehab” on VH1, Dr. Drew and his current patients — especially former Guns N’ Roses drummer Steven Adler — coped with the news that Alice in Chains singer Mike Starr had died of an overdose. Starr participated in the show’s third season last year, and he and Adler, who is also a very serious addict, became close. Starr died last March while filming on the current season was under way.

4) Jimmy Kimmel’s Ken Burns obsession: We always love it when TV spoofs itself, and we especially like it when Kimmel takes a few affectionate whacks at Burns, the affable, undisputed king of PBS documentaries. This week, Kimmel combined drunken footage from Youtube with historical film to produce this promo spot for Burns’ upcoming miniseries about Prohibition, premiering in October.

5) Jesse’s criminal education on “Breaking Bad”: Jesse (Aaron Paul) might be on the way to losing his amateur status — as a criminal — thanks to his apparent apprenticeship in professional criminality with meth-ring jack-of-all-trades Mike (Jonathan Banks). In last Sunday’s episode, Jesse impressed Mike with his resourcefulness in one of this show’s best scenes so far this season.