Rimsky-Korsakov’s bizarre final fantasy, puffing up Pushkin's short verse-tale to unorthodox proportions, has done better in Britain than any of his other operatic fairy-tales. That probably has something to do with its appearance in Paris, six years after the composer’s death in 1908, courtesy of a brave new experiment marshalled by that chameleonic impresario Sergei Diaghilev.

When Ryan Gander’s wife wanted a designer lamp, the versatile artist knocked one up from junk. She was so impressed he sold it as an artwork and by now has made 55 in his garden shed. Three are here in Manchester, made from foil food trays, a guitar stand and concrete. These pieces are quite unrepresentative of the rest of this highly conceptual show, but in a diverse, major survey there appears to be no truly representative way in.

This summer, Tate St Ives turned 21. And this makes it as good a time as any for an exhibition repositioning the artists who were associated with St Ives, the small harbour town in Cornwall, where you'll find the gallery on the sea front at Porthmeor Beach. 

Digital Revolution begins with an archive section taking you back to the 1970s when Ralph Baer developed a video game allowing punters to play ping pong on TV (below right: poster for the original Pong arcade game) and Steve Jobs worked on Break Out, in which a virtual ball bounces off a bank of horizontal lines.

The National Gallery has a range of personas it adopts for its exhibitions, and for this one, about colour, it has deployed the po-faced, teachy one. The pompous tone is because it’s not just about art this time, there’s science in it, which makes it extra serious. And we know it’s science, because the posters and promotional material look like the cover of a chemistry textbook, with bursts of colour against a black background reminiscent of an explosion in a laboratory, or something exciting in space.

From Apocalypse Now to Blue Velvet to Speed, as a screen presence Dennis Hopper grew ever more scary. Lately gallery-goers have got to know another side of Hopper via his painting. Now there is a belated run-out for his work as a photographer, although work is maybe the wrong word. He spent much of the Sixties with a camera slung round his neck, but didn’t make a dime from any of his pictures. “They cost me money,” he said, “but kept me alive.” Hopper rode out of the decade on a Harley as director of Easy Rider and he didn’t pick up a camera again.

Bridget Riley’s mural for St Mary’s Hospital in Paddington, which was unveiled in April this year, is something I’ve seen only in photographs. And on seeing it for the first time my reaction, I’m afraid, was, “Oh no". It obviously didn’t help that the photographer had wildly exaggerated the one-point perspective, so that the parallel lines of two facing walls converging sharply made you feel the vertiginous pull of a rabbit hole.

The windows of Hepworth Wakefield command some attractive views, and for the present show looking out the window might even be a valid alternative to looking at the work. Curator Eva Badura-Triska reports that Austrian artist Franz West was a believer in the aura or the atmosphere of an art work. It hardly matters where you look. As if to prove the point there are installations which include chairs facing away from the work, or sofas angled to provide little point of focus. Sit still for as long as you want and soak up this extensive exhibition.

When a large and ambitious group exhibition is mounted on a particular theme or subject, in this case the human figure in contemporary sculpture, it’s always interesting to note what gets left out as well as what goes in. It’s reasonable to ask what story is being promoted under the heading of a general survey. Here are 25 sculptors, all but one from Europe and America, spanning the past 25 years. You might ask, “But where is our own Antony Gormley?” After all, Gormley has been the “go-to” British sculptor whose subject for the past quarter of a century has been the human figure.

In the midst of ferment as the arts world faces fast-shrinking public subsidy, Sir John Tusa, former managing director of the BBC World Service and the Barbican Arts Centre, publishes this week a brisk new book that urges arts and politicians to reject the emotive clichés and lazy token battles and focus on what matters. In Pain in the Arts, Tusa urges that both sides take personal responsibility for an essential part of human life.