Liberal Party of Canada
Harper & the Conservatives was an incendiary ad that raised doubts about Stephen Harper's motivations.
New Democratic Party
This comparison ad between Paul Martin & Stephen Harper was similar to a Liberal ad that compared Brian Mulroney and Mike Harris to Stephen Harper. Same technique, different parties.
Another one of the NDP comparison ads that took a swipe at Paul Martin and Stephen Harper.
Ed's Back! was the punch line of this tongue in cheek ad, originally done for Rick Mercer's show. Apparently was the most downloaded thing on the NDP site.