On September 19, a gubernatorial debate was held in Grand Junction, Colorado. The independent candidate, Greg Lopez, was invited into the debate, but none of the four minor party gubernatorial candidates were invited. The sponsor was Club 20, a prominent business and civic group that traditionally sponsors candidate debates. The debate was not televised live but it will be available on youtube.
This article explains the odd logic used by Club 20 when it decided whom to invite. The four minor parties candidates were nominated by the Libertarian, Constitution, Unity and Approval Voting Parties.