Don't mention it.

I've found some more information, for those who might be interested.

The debates will be held at Columbia University, and will be televised on C-SPAN from 8-10 pm EST.

If there are seen as a success, there may be more of these debates in the works before November 4th.

The criteria is the candidate must be on the ballot in enough states to allow them to win the minimum number of electoral votes, which is 270. Seems like a very sensible benchmark to use for entrance into any truly democratic presidential debates.

There is lots of good information to be found at:

http://www.democracynow.org