Prime Minister Stephen Harper announced yesterday he has asked Governor General Michaëlle Jean to prorogue the current session of Parliament. The session was originally supposed to start again on September 17th. This means the Parliament would not sit again until October 16th, starting the Second Session of the 39th Parliament. See the Prime Minister's Sept. 4th announcement.
According to a report by the CBC:
the move sets the stage for a non-confidence vote that could trigger an election campaign — a vote and election campaign that could turn on Canada's commitment in Afghanistan.
Opposition parties must decide whether they want to bring down Harper's minority Conservative government, elected 18 months ago, and face another campaign.
All Bills in progress will Die on the Order Paper, but some may be reinstated once sitting resumes. More general information written for the public is available from the House of Commons Fact Sheet: Prorogation (note the disclaimer).