SPORTS 

Golf: the most famous golf course in the region is the Alberoni Golf course. http://www.circologolfvenezia.it/  

Sailing: Check out the marina at San Giorgio Maggiore island, or one of the marinas along the Giudecca island;

Cycling :  Rental bike  Mira, Venice. Deliver pick up and return of bikes at bus stations, railway stationsor at your b&b/hotel (available for a small fee). Sightseeing bike toursitineraries on Pellestrina Venetian ancient fishery island (only in Venice forcyclists), Venetian villas on Riviera, hills of Prosecco, Venetian WWF OasiValley Averto, Padova and Treviso regions itineraries with sporting supportguide.

Swimming: if the weather is nice enough, head to the Lido (vaporetto line 1, additional lines seasonally and weekends) from May to September. There, you can enjoy the beach or the pools of the Moorish Excelsior hotel or the classical bel epoque hotel des Bains (entrance fee). The Cipriani and San Clemente hotels don't allow outside guests to the hotel. The Olympic sized indoor pools at Sant'Alvise and near Giudecca at Sacca Fisola are open to the general public and have open swim schedules which vary seasonally (entrance fee - August usually closed).

In-line skating: the only place for that is the rink at Sant'Elena in Castello   :D

Tennis: as with most sports, it is much more widely available at Lido or on the Mainland, but some hotels and clubs, such as the Hotel Cipriani also have facilities (though limited in number).

Jogging: probably the only sport you'll be able to really practice in  Venice itself. best to do it very early in the morning to avoid the hordes of daytrippers flooding the streets of the city. It is also a great way to see the city, and enjoy a true "Woody Allen" moment!

Rowing: The most famous rowing club is the Canottieri Bucintoro http://www.bucintoro.org/, but as you can imagine being in the middle of a lagoon, there are many many others, most of which require membership.

ACTIVITIES  

Depending on when you go and visit the city, there may be different activities going on. The best place to look for them is in a free guide, usually available at most hotels (and definitely available at the tourist board near Giardinetti Reali near San Marco) called "Un ospite di Venezia" (i.e. " a guest in Venice").

Biennale: This world famous art exhibition is held from Juneto November every two years, as the name implies. It is held in theGiardini della Biennale in the Castello sestiere, overflowing often with special exhibitions and events to the area of the Military Arsenaland Shipyards. In alternate years of the Biennale d'Arte (odd numbered years) there is a Biennale d'Architettura for Architecture (even numbered years). The Biennial Foundation also organizes other cultural events throughout the year tied to theatre, dance, music, and the world famous "Festival del Cinema" held at Lido every year in late August-early September with a cast of international stars that is perhaps rivaled only by Cannes.

Carnival: this world famous event is rivaled only by that of Rio for sheer extravagance. Costumed people flock to the street, music and processions fill Piazza San Marco, and the atmosphere is quite unique. It takes place in the three weeks leading up to Ash Wednesday and Christian Lent (the 40 days of fasting before Easter) usually from mid-February to early March, and ends with a spectacular Martedì Grasso (Mardi Gras or "Fat Tuesday").

Gondola Ride: Being a city built on water, one of the best ways to discover Venice is at water level, gliding along in a gondola, guided by a gondolier who is knowledgeable of the city. There are many "rogue" gondoliers who improvise, often with second hand or slightly off-category imbarcations (sometimes not even officially "gondolas"), making up prices on the spur of the moment and cutting the ride short earlier than promised. But there are several Cooperatives of gondoliers which require language skills and Venetian history and information tests, guarantee fixed rates and trip times and can reserve spumante (sparkling wine) and music (singers and/or musicians)  too, whether for a romantic twilight ride for 2, or a festive singing daytour for 25 inside-by-side gondolas.

Redentore Festival: this mid-July holiday commemorates the end of the plague of 1576. On Saturday night, fireworks light up the Venetian sky and are reflected magnificently in the waters of the lagoon in front of Saint Mark's Square, and gondolas, motorboats and gran-turismo yachts are all decorated with lanterns and echo of music and laughter. It is also customary to eat roast duck and watermelon amongst a horde of other much more local specialties impossible to find outside Venice, such as "sardee in saor" (onion marinated sardines) or "bigoi in salsa" (extra-thick spaghetti with an anchovie based sauce) and lots of local white table wine to wash it all down. All this creates a very festive atmosphere to be enjoyed by all. It is usually celebrated the eve of the third Sunday in July, followed on Sunday by celebration, processions on a a ceremonial bridge constructed for two days every year across the Giudecca Canal to the "Chiesa del Redentore" designed by Andrea Palladio, and a commemorative gondola regatta race.

Regata Storica (Historical Regatta gondola rowing race): held the first Sunday in September, this is actually a day of races up and down the Grand Canal. The most accomplished gondoliers row two-by-two in "gondolini" for what is considered the "crown" of the Venetian Regatta rowing season. Other races include the local clubs (one for each "sestiere" or neighborhood) row six to a "caorline", the women who compete paired in "mascarete", and young rowers' that use "pupparini". The competition is usually very fierce, so much so that several recent editions have seen arguments and fights break out amongst contenders before, during, and after the races. Past editions have also seen special events such as a "student regatta" with all of the local universities faced off against each other.

If you happen to be there it is not to be missed; there is a spectacular procession of boats carrying all Venetian dignitaries down the Grand Canal followed by several races.  http://www.regatastoricavenezia.it  gives you an idea; you don't have to pay - just stand by the Rialto and take in the colour and the costumes.

It is well worth planning a trip to Venice if you are going to be in the vicinity at the time - although it was very busy this year, there was no problem getting to see everything. 

Venice Marathon: this running marathon runs through the most magnificent route, from the Palladian Villas on the river Brenta through the Zattere and the Piazza San Marco. An absolute must for runners. It is held in October. www.venicemarathon.it

Vogalonga: generally held the last Sunday in May each year for more than three decades has seen the non-competitive rowing regatta Vogalonga. People from all over the world show up to row around the Venetian Lagoon, in kayaks, rowboats, and "typical" Venetian gondolas, either singly or in groups. The only limitation is that it must be hand powered rowing that propels the vessel through the 30K of the regatta's route from Saint Mark's Square out to Burano, Sant'Erasmo, Murano and back to the Custom's House in front of Saint Mark's again to finish.