This week’s Saturday Night Live was all over the map: lame one minute, funny the next, and at the end, there was one sketch that — well, I’ll get to it in a little while. As host, Blake Lively was firmly in the plucky-not-awful tradition. It was one of those SNLs when you felt the rest of the cast had been enlisted to make sure the host was always surrounded by enough activity so that it wouldn’t look as though she was responsible for the dull patches. She did not do her version of Riverdance, which she performed so charmingly on Jimmy Fallon and had promised Fallon’s audience she’d do on SNL as well. That, I think, would have gone over a lot better than the Muppet Show scene that occurred during her monologue.

Early on there were a couple of dud political sketches — SNL got its obligatory Salahi party-crasher joke out of the way in the cold-open, and a little later committed its obligatory Tiger Woods sketch, framed as a CNN news report. I think it’s a good rule of thumb to never parody anything to do with CNN — the tediousness of that network infects everything it touches.

The night’s only Gossip Girl reference that I caught came in a sketch called Gossip Girl Staten Island. Its trite premise – that working-class folks are crass – was rendered instantly irrelevant earlier this week, when MTV premiered the reality show Jersey Shore, a far more vulgar and vivid piece of junk-TV.

The “Digital Short,” with Rihanna singing in a kiddie classroom with (teacher?) Shy Ronnie — Andy Samberg mumbling in a red wig — was pretty funny, mostly to hear Rihanna sing her advice to Ronnie in the form of lyrics (“Move the mic away from your face”).

A high point: The fake ad for the “Rockspit Underground Rock Festival” was a barrage of good jokes capturing the junkiness of a cheap commercial, from the names of the bands on the bill (“Gunt!” “Thurdersex!”) to the special guest stars (Mark Fuhrman; ventriloquists on stilts), and… “Everybody gets pitchforks!” Loved that:

Rihanna performed one number wearing some faux chainmail more fetching than the song itself. The other performance, “Hard,” with Young Jeezy, felt as leaden as chainmail.

The best joke on “Weekend Update” was about ecstasy pills found in the shape of President Obama’s face (true story). Seth Meyers said, “The high is characterized by a brief, powerful high followed by a long, slow comedown.” Abby Elliott also did a good Brittany Murphy imitation during this segment. Two things, though: Her punchlines were limp, and, sorry, but who really cares about Brittany Murphy’s career?

Lively did her best to approximate some urban slang and swagger during a Mrs. Hastings goes shopping sketch, with Thompson in drag as her mother (“by marriage, not vagina”). This same sketch has been used at least once before that I recall, with Scarlett Johansson in Lively’s role. It wasn’t too amusing then, either.

Andy Samberg broke out his excellent Keanu Reeves impersonation to lift a wanly-written sketch about To Catch A Predator host Chris Hansen getting his own talk show.

But now the evening’s final sketch, often the graveyard for dozy dullness. Will Forte played a NASA recruiter; Jason Sudeikis was a pompous astronaut-candidate being interviewed. Asked by Forte not to eat from the bowl of potato chips on his desk, Sudekis did so anyway, provoking a bellowing, screaming fit from both Forte and Lively, who entered as an assistant in a red wig. “Potato chip thief!” and “You don’t take people’s potato chips!” were among the epithets yelled.

The sketch was so pointless, its details so absurd (Sudeikis regurgitating the potato chip into Forte’s hand; Sudeikis huffily taking with him a “hemorrhoid doughnut” which we hadn’t previously seen him sitting on), and went on for so long, that it went beyond bad and came out the other end. Forte and Sudeikis were so ferociously committed to this material, I ended up admiring the hell of out them. I didn’t laugh, but I had to hand it to them. It was kind of like SNL‘s version of There Will Be Blood. I was glad I witnessed such a strenuous non sequitur.

What did you think?