Last Night's TV: Bird-brained folkies swoop to conquer

Flight of The Conchords, BBC4; True Stories: Following Sean, More 4; Sex In The Noughties, Channel 4

I don't know what strange eddy in the comedy ether has resulted in two current series revolving around an oddball partnership and ornamented by brilliantly terrible musical numbers, but if you're having difficulty distinguishing between The Mighty Boosh and Flight of the Conchords, just remember that Boosh is the one that looks as if it's been written on acid and the Conchords is the one that looks as if it's been written by someone who thinks that acid is what you put in car batteries. Boosh, I suspect, is for those who like their comedy amplified and remixed, treble and bass turned up to the maximum, and lots of weird synthesiser effects thrown in for good measure. Conchords, by contrast, is playing a sweetly naive acoustic set and you're going to have to pay attention if you don't want to miss the good bits. Of which there are a lot. I wrote a while ago that I was falling in love with this series. We're now married and I'm thinking about children.

Bret and Jermaine had a brief moment of excitement this week, when a member of the audience came up and offered spontaneous praise. Usually, they have to make do with Mel, their loyal stalker, when it comes to post-gig adulation, but this man was a stranger and, yes, still overflowing with enthusiasm. "The idea of a pair of naive idiots from New Zealand... it's so simple, it's genius! You just pick an obscure country that nobody's ever heard of... it's very funny! So, where are you guys from?" The point being, if you haven't been watching, that they are from New Zealand and their gauche folk act isn't intended as a spoof. Murray, New Zealand deputy consular attache in New York and the band's hopelessly incompetent manager, was getting depressed about their failure to secure a recording contract, so when the boys discovered their new fan was a "semi-professional actor" they recruited him to boost Murray's morale by - for once - letting him down with some encouraging words.

Unfortunately, the stooge got so carried away by his role that he ended up offering the group a $2m deal, despite Jermaine's best efforts to scupper the negotiations, an enterprise in which he was not much assisted by Bret, who kept forgetting that the whole thing was a consoling fiction anyway. Thrilled at this new development, Murray spent a lot of money on filming the band's Lord of the Rings song ("Frodo - Don't Wear the Ring"), taking the role of Gandalf himself and yoking in Mel to gibber elvish as Arwen. It was very funny - four words that work neither as persuasive argument nor adequate description. But if you like the idea of a New Zealand tourist poster that reads "New Zealand - Why Not?", then you may fall in love, too.

The bohemian life was also the subject of Ralph Arlyck's True Stories: Following Sean, which was a kind of meandering sequel to a student piece he'd made in the Sixties, when he lived in Haight-Ashbury at the very height of the countercultural revolution. His first film was about Sean, the four-year-old son of a couple who lived upstairs in a haze of marijuana smoke and social experimentation. Returning to find out what had happened to the boy, Arlyck also conducted a kind of 30-year audit on the ideals and lifestyles of the flower children. There was no clear-cut indictment here. Sean seemed to be on good terms with his parents, despite his chaotic childhood, though he had ended up training to become a lawyer and working all hours to support his own child. But there was a kind of unintentional comedy to the way in which Arlyck had recorded virtually every detail of his own life to feed into his solemnly self-indulgent film. His own wife, Elizabeth, had eventually departed to Paris to teach for three years, a development that Arlyck reported in glum, Eeyorish tones. I'm guessing it was the only way she could get away from the relentless poking of his camera lens.

Sex in the Noughties recorded the edifying combat between Nuts and Zoo, lad mags that aimed to get at the wallets of their male readers by going in through the trouser zip. Nuts initially launched as a magazine that fathers and sons could share without embarrassment, but as soon as Zoo dived downmarket, it followed suit, until both titles were struggling to out-nipple each other. In doing so, they made several glamour models very rich, cemented Abi Titmuss's place in the national consciousness and led to the establishment of the Assess My Breasts website, an important service for girls of low self-esteem, which allows them to upload a phone-pic of their breasts to the Nuts website and have them marked out of 10 by blokes who have nothing better to do with their free hand.