The Venice Biennale (June 4-Nov. 27) is always the same, and always different.

It’s the world’s most colossal jamboree of contemporary art and reliably huge -- in fact, huger every time. Long ago it overflowed the public gardens where the whole event began, and now there’s scarcely a church or palazzo in town that’s not pressed into service as an exhibition space or party venue.

The individual ingredients -- artists, curators, stunts -- are reshuffled every time, and there’s usually a talking point. For example, the exhibition organized by the curator of the Biennale, which generally comprises enough cutting-edge video and installation work to fill a shopping mall, will this time also contain three large canvases by Jacopo Tintoretto (1518- 94).

In the national pavilions -- selected by the individual countries, and making up in total a sort of avant-garde UN -- there will be no Old Masters, but plenty of media more exotic than oil paint. Jennifer Allora and Guillermo Calzadilla (representing the U.S.) are displaying, among other items, a 52- ton military tank, a gigantic pipe organ incorporating a fully functioning ATM, and a team of eight trained athletes.

That will be hard to upstage, though the French installation specialist Christian Boltanski -- the best-known participant, Tintoretto apart -- is likely to be a contender for top prize.

Royal Academy

In London, there’s the more traditional nuttiness of the Royal Academy’s Summer Exhibition (June 7-Aug. 15), an annual event in the art calendar since 1768. A large, transparent, brilliantly colored sculpture by Jeff Koons already has been placed in the courtyard of Burlington House, next to the statue of the RA’s founding president, Joshua Reynolds. This sums up the stylistic incongruities that characterize the Summer Exhibition, sponsored by Bank of New York Mellon Corp. (BK)’s Insight Investment.

Another unexpected juxtaposition of Old Master and contemporary artist will be on show in “Twombly & Poussin: Arcadian Painters” at Dulwich Picture Gallery (June 29-Sept. 25). Cy Twombly, the veteran American painter, noted for abstract splatter and graffiti-like jottings, is not the most obvious art historical partner for the French classicist Nicolas Poussin (1594-1665). They do have a few things in common, including both being expatriates dwelling in Rome.

At Tate Britain, there will be a survey of the first U.K. avant-garde movement of the 20th century, “The Vorticists: Manifesto for a Modern World” (June 14-Sept. 4). As often with plucky British contenders in various fields, notably sport, the nagging question about the Vorticists is: Were they really good? This should help clarify the answer to that question.