Actually, there is often not that much happening at La Fenice. They just don't stage that many operas. They do have a fair amount of symphonies and chamber music that you can sometimes catch. La Fenice has wonderful cozy rooms for chamber music. Also, don't overlook Teatro Malibran, as mentioned above. Not every Venetian can afford an opera ticket for 160 per seat at La Fenice. Malibran is sort of like the neighborhood opera house, where the locals go. Won't generally be showing huge stage productions, but I recently saw two wonderful operette on a program, one by Wolf, the other by Weill. Most people in the audience were in 7th heaven. A little less formal, as in during the break the crowd goes out to find a local place for a quick cicchetto and glass of wine, then head back in. La Fenice is great if schedule allows, a symphony there is also super, and chamber music, which will tend towards newer classical, is also worth it, but not the only game in town. Be careful with the boxes in La Fenice. No front row, you probably don't want it. Mostly obstructed view. Be careful with the seats.