Last Night's TV - The Family, Channel 4; Imagine, BBC1

Is that what people see! I'm going to stay inside!" exclaimed Ayo, catching sight of himself in the video recording of his father's 60th birthday. Ayo wasn't happy with how he looked on screen, so goodness knows how he's going to cope with the next few weeks as The Family, Channel 4's 24/7 surveillance operation, returns for another series in which it offers us the belly-button lint of domestic life – fuzzy, undistinguished, its origins unidentifiable but also curiously satisfying to winkle out of the crevices. Like belly-button lint it is also astoundingly intimate, either because the participants just couldn't be bothered to put on a front in the first place or because the presence of so many cameras makes it impossible to keep up an act without going mad.

This new series is about the Adesinas, a Nigerian family living in Hackney, who offer a useful biopsy slice of the immigrant experience. The patriarch, Sunday, and his wife, Vicky, clearly think of themselves as predominantly Nigerian – a church-going couple dedicated to making their small business a success and getting the children raised right. The four children – from 27-year-old son Ayo to 15-year-old daughter Ola – are culturally of dual citizenship, British through and through but linked by birth to Nigerian traditions and style. But what's unique to them – as far as a general British audience is concerned – quickly gets eclipsed by what isn't.

Take the stepladder scene as a case in point. Vicky, rising early to begin icing her husband's 60th birthday cake, for some reason picked up an aluminium stepladder on the top landing and carried it – with all the appearance of consideration for her still-sleeping family – down to the kitchen. I don't think she missed a step she could clank it on, and she added to the noise by tunelessly droning out a religious hymn. There was no narrative and no consequence to this long sequence. You didn't find out what she wanted the ladder for and it didn't lead to an animating row. But it was funny and it was life, as it's lived by a lot of us. I enjoyed the battle over the kitchen radio too – volume knob twisting ceaselessly one way and then the other as different generations passed through.

Sunday doesn't appear to be a demonstrative father. Olu, 23, and planning to inherit the family business one day, thinks that more people should be like his father but doesn't have any illusions that it would lead to an emotionally open nation: "There won't be no kissing and hugging going on," he said, "but things would get done." Ayo, on the other hand, seems to be pinning his hopes on a career in rap: "I'm young and I'm black, surrounded by crack," he chanted on the half-landing – an attempt at keeping it real, which didn't entirely square with his actual circumstances. He is young and he is black but on this evidence he's surrounded by computer displays, on which he earns a living designing websites. Sunday's 60th birthday was a triumph, incidentally, celebrated in grand Nigerian style after church, and not in the least tarnished by his discovery, a couple of days later, that he'd been celebrating his birthday on the wrong day for the last 50 years.

Imagine's film about the Chinese artist Ai Weiwei reserved the one thing that most people already know about him for a hasty back announcement over the final credits, as Alan Yentob mentioned that health and safety considerations had limited access to his Tate Turbine Hall installation of 100 million hand-crafted porcelain sunflower seeds. On film, visitors rhapsodised about the sensual pleasure of burying themselves in the seeds and the Proustian memories of childhood it conjured. After which Yentob forestalled a rush to the Southbank by explaining that none of these joys were available any longer. You couldn't blame them for not making more of it though because this was a fascinating film, and the fiasco over ceramic dust would have made for an unjustly deflating ending.

It would have been interesting to know how Ai Weiwei felt about it though, because he appears to be an exacting judge of finish. In one startling scene in the film he was shown touring a factory that had been working on an installation for him, destroying giant ceramic vases that had, for some reason, fallen below the standards he required. Perhaps this was an art work in itself – or an allusion to one – since one of Ai Weiwei's early pieces showed him smashing a valuable Han dynasty urn. Either way it was a smashing bit of film, effectively solving the art documentary's perennial difficulty in making aesthetic discrimination dramatic to watch.

There was an odd paradox here. Ai Weiwei has pretty consistently been in trouble with the Chinese authorities – courageously campaigning for a proper inquiry into the death of schoolchildren during the recent earthquakes and suffering beatings and surveillance for his pains. At the same time he collaborated in the design of the Bird's Nest stadium in Beijing and clearly still has an internet connection, because he conducted part of his interview with Yentob by webcam, after the BBC's request to visit him in China had been turned down. In other words, the Chinese authorities appear to be simultaneously infuriated by him and proud of him, as an artist of international standing. One can only hope it buys him enough space to continue working.