Venice Carnival

[coccinelle]

Has anybody stayed in Venice during the carnival? On research over the net I realise it gets very, very crowded. Can someone tell me how crowded? Will we be able to get to visit St Mark's and Doge's Palace without queuing an hour or more in the cold? Is it less crowded during the week? We're there 5 nights so could work round the busiest times. I hope we haven't slipped up by booking this...