Biennale in Venice every year - the Art Biennale in odd-numbered years and an Architecture Biennale in even-numbered years. The Art Biennale is the better-known and larger of the two, but both give added interest to the city's visitors over a period of several months (generally June-November). Although there are major exhibition spaces at the Giardini and Arsenale sites, my favourite thing about the Biennale is the access to smaller, private spaces.
Many 'national pavilions' and associated exhibitions are housed in Venice's palaces, halls and churches. These are almost all free and many offer the chance to visit an interior you would never otherwise see. Sometimes this is a last chance. Two of the finest palaces I've visited for Biennale exhibitions in the past have now been renovated and altered; they'll never again have that authentic decrepit charm which made them magical. (One is now yet another luxury hotel chosen by George Clooney for his wedding celebrations). Once Venice's historic buildings are modernised and converted to hotels or private dwellings, a lot of their character will disappear; as will easy public access. So getting into these buildings when they are temporarily open may be a once-in-a-lifetime chance to experience a bit of history. You'll also, of course, see an art display - although the standard can be highly variable and to be honest I am almost always far more interested in my surroundings.
There are maps available of Biennale-affiliated shows, and you'll see posters and sandwich-boards outside palazzi as you walk around Venice or cruise down the Grand Canal. I've not really bothered with the Biennale this year; the exhibitions can get pretty tedious and
Conservatorio di Musica Benedetto Marcello (it has housed the municipal music college since 1897). It was once one of the grandest private palaces in the city (perhaps the grandest).
Having only ever seen the building from the outside, I was fascinated. Built between the 17th and 18th centuries for the hugely-wealthy Pisani family, the palace is even more imposing inside than you would guess from the splendid exterior. The most striking features are its two internal courtyards, separated by four storeys of loggia, and the way the building climbs upwards towards the sky.
This year there are two Biennale exhibitions housed in the Conservatorio, giving visitors the chance to explore two sections of the building: The Sound of Creation: Sound Paintings by Beezy Bailey and Brian Eno and the Angolan exhibition On Ways of Travelling (both closed on Sundays).
The first of the two exhibitions (with paintings to study and headphones for listening) is displayed up the length of a grand monumental staircase. The stairs climb up and up, and once you finally reach an attic room at the top and peer through its windows, you can see that this must be among the tallest buildings in Venice. You also get an idea of how vast and rambling the building is; this is just one staircase in one corner of one courtyard. Piano music drifted onto one landing through the closed double doors of an auditorium (I peeped through the crack between the doors). Off another landing I caught a glimpse of a meeting where modern business-suited attendees contrasted sharply with the ancient and faded grandeur of the surroundings.
The second art exhibition is housed on a piano nobile at the far side of the building, above the entrance hall, in a long frescoed chamber with chandeliers. When the Pisani family had money trouble in the nineteenth century they sold off the palace and its contents, including important works of art, but the wall and ceiling paintings are still in situ.
Getting a chance to nose around Palazzo Pisani was an unplanned treat. For me it was also a reminder of how many fascinating sights there are in Venice; you can spend years here and still come across something new. It is always worth keeping an eye open for special events and openings, and the Biennale is a great chance for this kind of off-the-beaten-track exploration.
The Art Biennale runs until 22nd November this year. As the Conservatorio is a music college, it may (perhaps) be possible to glimpse Palazzo Pisani's courtyards on other occasions. The building may occasionally be open to the public for other special events. Many of Venice's other buildings are also open to host Biennale exhibitions. A map of Biennale locations can be found here (pdf file).
More of my insider tips for visiting Venice including out-of-the-way sights can be found in Venice: Italy Heaven Guide.