On October 12, three candidates for U.S. Senate in Alaska debated each other.  See this story.  The three candidates were Republican nominee Joe Miller, Democratic nominee Scott McAdams, and write-in candidate, incumbent U.S. Senator Lisa Murkowski.  This is almost certainly the first time any write-in candidate for U.S. Senate or any other statewide office has ever been invited to debate the major party nominees, in any state.