B.C. or BS?
In 1997, Labatt began to sell Kokanee in Ontario. Kokanee was originally sold in British Columbia, and its marketing is heavily associated with mountains, glaciers, sasquatches and the like.

Labatt's main competitor, Molson, seized on the fact that Kokanee sold in the Ontario market was actually brewed in London, Ontario. (For those unfamiliar with Canadian geography, the London area is decidedly not mountainous.) To educate the beer drinking public, Molson placed ads in various print publications with the tag line "B.C. or BS?" I think that there may have been some radio spots as well.

Rocky Mountain Truth
By 2006, it appears that anyone at Molson who remembered the ridicule invited by implying that a beer came from a different place than it actually did had moved on. In any event, Coors Light was being aggressively promoted for the Ontario market, with much imagery associated with the Rocky Mountains.

The Coors Light sold in the Ontario market was actually brewed in Etobicoke, Ontario, which is possibly even less alpine than London. This allowed Labatt to create the "Rocky Mountain Truth" campaign. A major element of this campaign was a website which no longer exists, but is archived by the Wayback Machine. For viewers from devices that don't support Flash, the images below give a flavour of the contents.