Grassroots groups in some Ontario communities, including Peterborough and Kitchener-Waterloo, are talking about whether it might be possible for opposition parties to co-operate and run just one candidate per riding against Conservatives in the next federal election.
There's a video at the link with a three minute segment from CBC News.
When this kind of thing comes from the top down -- from party leaders or even activist organizations with a national profile — I tend to dismiss it as being gimmicky and undemocratic. And unlikely to work. If it's going to work at all, this is the way it'll happen — from the bottom up.
It has the added advantage of making it a bit more difficult for the Conservatives to fight. It's relatively easy for them to demonize the members of other political parties but even the odd Conservative backbencher might hesitate when he finds he has to demonize his own constituents, including his neighbours and people who previously voted for him.
In case it's not obvious, the title is a joke. I think the word "coalition" and the concept behind it badly need to be rehabilitated. But a coalition is formed after the votes are cast. The voters get to go first.