Visual Arts: At home with the Ideal World Exhibition

`Ilya & Emilia Kabakov - The Palace of Projects': The Roundhouse. `Whitechapel Open'. Whitechapel Gallery

Peter Mandelson, making the opening speech, was reminded of his Dome. He'd just had a tour of The Palace of Projects - a labyrinthine structure created by Ilya and Emilia Kabakov, in the Roundhouse at Chalk Farm. And perhaps he was right to be reminded. Who knows yet? For us listening to his words last week, the most obvious point of similarity was that, with the Palace, as with the Greenwich Dome, Mr Mandelson found the experience "impossible to describe".

It is not, but it would take a while to tell it all. The Palace, an Artangel project, represents three years' work by the Russian husband-and-wife team. It's a piece of indoor architecture, a round white two-storey block, which rises in a snail-curl under the roof of the old theatre, like a DIY version of some optimistic blueprint of early modernism. Go inside, and you're in a network of rooms, divided by walls made of a sort of solid gauze, semi-transparent, so that visibility spreads into the adjoining chambers and gradually fades.

You walk through, as if in a mist. And inside every room the Kabakovs have placed a handful of "projects": wooden desks to sit at, on each a sheet of paper with a written proposal (plus diagrams), and an illustrative 3D model, scale or actual size, nearby. The proposals outline useful schemes for improving things and the scope is wide - the mind, the home, society, the planet, the cosmos. It's an Ideal World Exhibition.

Examples. A proposal for "The Punishment of Household Objects", to take out your grievances on the inanimate world - a curtained-off "black corner" where "guilty" pots and buckets can be stood. Or there's "What else can be said about this?", a proposal to encourage public reflection: a glove, say, is placed on the ground, and lecterns placed around it, each with a different meditation on the glove.

It's clear, of course, that these plans are improbable, or impractical, or wholly impossible - frankly a bit mad. The proposals are written in a tone of naive certainty and helpfulness. There are references to the "noosphere" and the harnessing of mysterious "energies". The models are constructed with enthusiastic, makeshift wonkiness, and the schemes themselves are often of the string-and-cardboard variety.

Each project is credited to a (fictional) Russian citizen as if the results of a competition for amateur inventors. You seem to have entered cranks' heaven. Is this some kind of satire? Is it just wacky?

Not quite either. It's certainly very funny, and the Kabakovs are presumably taking a poke at old Soviet-style designs for world betterment, and at the abiding Russian interest in weird science, in parapsychology and what they call cosmology (meaning something much more supernatural than it does in the West), and at the utopian impulse generally. These things are lightly mocked - but at the same time honoured.

The Palace of Projects is a work in praise of human wishes, while alive to the ways a single bright idea can cause more problems than it solves and easily grow into tumbledown megalomania. It's a monument to the spirit of optimism. It must be seen to be believed, and disbelieved.

THE Whitechapel Open is open. Open shows are good. They have the minimum of overall agenda, being a collision between the miscellaneous works submitted and the various tastes of the selectors. And they flagrantly put art-works in competition with each other, not only for selection, but (once chosen) for the attention and favour of the viewer. So, compared with solo shows and pro-actively curated shows, the viewer feels much more in charge of the experience. This is good.

That's the hope anyway, and this biennial exhibition always promises well. This year, it's spread over three places - the Whitechapel Gallery itself, The Tanner in Bermondsey and various sites around Canary Wharf. Work of every sort by about 130 artists is on view. It should be various at least.

It is and it isn't. And thinking about agendas, didn't I read one of the selectors saying that they went for anything that made them laugh? It does look that way. There are some sober works here, but Novelty Shop is the dominant impression.

Ilya & Emilia Kabakov - The Palace of Projects: The Roundhouse, Chalk Farm Road (Tue-Sun 12-8pm, last admission 7pm) Until 10 May. pounds 5, pounds 3 concs.

Whitechapel Open, Whitechapel Gallery, Whitechapel High St (11-5, Tue- Sun), The Tannery, 57 Bermondsey St (12-6, Tue-Sun); at Canary Wharf (12- 5, Wed-Sun). Until 31 May. Admission Free

Tom Lubbock