Preview RECOMMENDED VIEWING THIS WEEKEND Martha Graham - the Dancer Revealed Sat 7.35pm BBC2 Is This Your Life? Sat 9.45pm C4 Witness: The Shadow of Hiroshima Sun 9.40pm C4

The most splendid activity pursuable in sultry weather is not to exert oneself into a perspiring shambles in the name of "health" or "fitness", but to watch other people doing so. Hence the popularity of Wimbledon and Test cricket, and hence also the attraction of the BBC's admirable new Summer Dance season.

Martha Graham - the Dancer Revealed (Sat BBC2) is a fine curtain-raiser, stuffed with lovely anecdotes about the extraordinary American modernist whose career spanned 70 years. She was universally accepted as a genius - partly, at least, for no other reason than that she acted like one. Agnes De Mille pops up wryly to say: "Martha was, of course, madly in love with Martha." And what a sweet glimpse of a golden age where law- enforcers were all aestheticians: one day at the Greenwich Village Follies, the cops were doing their regular modesty check. Only Martha lacked the regulation shirt beneath her skimpy outfit. "What about her?" asked one policeman. His superbly cultured colleague answered: "She doesn't have to - she's art."

So, in a somewhat different sense, is Andrew Neil, his Is This Your Life? (Sat C4) being a very Nineties kind of interactive installation piece. The unsuspecting victim wanders into a Danteesque studio studded madly with giant video screens which carry, mostly, shots from various angles of Andrew Neil's shiny fizzog - as if, for Neil, being telegenic were merely a matter of pixel acreage.

This is not to detract from Neil's skills as an interviewer. His aggressive grilling is a compliment to the articulacy of Peter Tatchell, controversial gay rights activist and leader of Outrage!. To the accusation that "outing" is a hypocritical invasion of privacy by those who complain about their own privacy being invaded, Tatchell ripostes heroically: "Saying they're gay is no more an invasion of privacy than saying they're left-handed or Catholic." Oh, if only everybody thought that way.

The exception to the dry, fact-laden character of the current slew of atom-bomb documentaries is Witness: The Shadow of Hiroshima (Sun C4), an instantly accessible, hugely powerful film written and directed by Tony Harrison, England's peerless poetic rhythmist. Shadow San is an anonymous man killed in the nuclear flash, who appears to the poem's narrator on the eve of August 6, leading him around modern-day Japan to discover how its characters are planning to commemorate VJ. The Shadow sees a neon sign saying "Parlor Atom" and thinks it must be a place of prayer and remembrance; it turns out to be a pinball arcade: "there are 30 million Japanese / spend their nights in 'shrines' like these".

What makes Harrison unique is his effortless commingling of the literary - the scheme of the poem borrows from the ghost scene in Hamlet and Coleridge's "Rime of the Ancient Mariner" - and the fearlessly demotic. One of the few buildings left in Hiroshima that predate 1945 is a Czech domed edifice whose skeleton has been left standing. The poem's dead man comments lugubriously: "'The force that blew the Dome apart' / said the SHADOW 'makes short work of art'." If you watch nothing else on television this year, see this.