Last Night's TV - Who Do You Think You Are? BBC1; The Adventures of Daniel, BBC3; Coronation Street, ITV1

It was a terrifically good idea of someone or other to marry celebrity with genealogy in the form of Who Do You Think You Are?, which is now in its seventh series and is one of the BBC's most successful exports of recent years. The Swedish version, for example, is called Vem tror du att du ar, which I intend to memorise and use next time someone gets uppity with me in Stockholm, although there's always a chance I might get my English-to-Swedish programme titles wrong and ask who wants to be a millionaire, which wouldn't be much of a riposte.

It's easy to see why the format has been successful round the world. Admittedly, the British obsession with celebrity is such that you could marry it with ostrich-racing or wood-staining and get a TV series out of it, and someone else probably will, but all that genealogical research at least makes us feel as though there's a vaguely intellectual pursuit going on, and that the celebrity dimension is secondary to the history lesson.

The obvious flaw of the series is that not everybody has interesting forebears. Apparently, Michael Parkinson warned the production team that they'd find nothing in his family tree, just miners and farm labourers on his father's side, and railwaymen and domestics on his mother's. They chuckled and assured him that they always turn up something interesting; besides, why shouldn't generations of miners and railwaymen yield a decent story or two? Six weeks later, however, the show was junked. There were no stories. Parky wasn't kidding.

A little unfortunately, given the BBC's resolve never to discriminate on grounds of race, colour, creed or class, posh people tend to make the best subjects, if only because they trail centuries of wills, deeds and flowery letters. Last week's edition, with the posh actor Rupert Penry-Jones, was modestly interesting, but last night the team hit TV gold, tracing the actor and comedian Alexander Armstrong back to William the Conqueror, via his 10-times great-grandfather, Edward Somerset, the second Marquess of Worcester.

Neatly, in The Armstrong & Miller Show, Armstrong once sent up both himself and the WDYTYA? format, hoping to uncover lots of grand female ancestors only to find that they were all listed in the records as whores. No such embarrassment awaited him last night, although he might have welcomed the odd whore among all the bona fide aristocrats. No self-respecting satirist should come from such a long line of nobs.

Still, he was endearingly gratified to learn about Edward Somerset in particular, an ardent royalist who lent King Charles (I think I heard this correctly) the 17th-century equivalent of £70m in today's money. During the Civil War, Edward tried to be a soldier and even a spy but was pretty hopeless at both; following the Restoration, however, he pursued a more successful career as an inventor, devising something called the water-commanding engine, which anticipated the age of steam power by almost two centuries. In 1861, indeed, the Victorian collector Bennet Woodcroft got so excited about Edward's invention, said to have been buried with him, that he opened up the marquess's tomb and searched it. Sadly, the water-commanding engine wasn't there, so Woodcroft consoled himself by taking the remains of one of Edward's fingers for his museum. Digital remastering, it would be called now.

No amount of digital remastering would have improved the pilot episode of The Adventures of Daniel, just some top-to-bottom rewriting. Not unlike the BBC's other new sitcom, Grandma's House, The Adventures of Daniel revolves in sub-Seinfeld fashion around a comedian playing himself, in this case the teenage Scottish stand-up Daniel Sloss. He seems like an engaging and talented lad, but he was ill-served by some gruesomely unfunny material, all constructed around the notion that his (Scottish) girlfriend's (English) dad didn't care for him, but thought that his (Scottish) girlfriend's (English) sister's (Scottish) boyfriend was the bee's knees. As the (Scottish) girlfriend's (English) mother, looking faintly as though she had wandered into the wrong rehearsal room, was Imogen Stubbs.

Some of the previews of this pilot were decidedly enthusiastic. One of them even featured the emotive word "funny". So maybe I was alone in finding it, on the whole, as funny as gastroenteritis. Coincidentally, trawling through the channels not long after watching it, I happened on a superannuated Scottish stand-up, Billy Connolly, on one of his world tours, and was reminded what "funny" really is. But then not everyone is tickled by Connolly, either. What "funny" is more than anything is subjective, so let me just say that The Adventures of Daniel might be your thing, but on this early evidence it certainly isn't mine.

Very much my thing, as regular readers will know, is Coronation Street. But I'm a traditionalist, a sucker for episodes in which the old-timers loom large, such as last night's first half-hour, in which, as Betty Williams (Turpin as was), Betty Driver got to show all her comic timing at the grand old age of 90, bless her. "Ooh, eh, what a palaver!" she said, on hearing about the process facing Becky and Steve McDonald before they could become adoptive parents. In the end the McDonalds were rejected, perhaps partly because Becky told the Weatherfield Council adoption panel that she didn't smoke, apart, obviously, "from two in the morning when you're bladdered". More TV gold.