I've called in a few times before and it was a lot of fun talking to Tom. However:
1. It was a bit scary
2. From my view, Tom is so consistently right on, and more deeply knowledgeable when it comes to pop culture and, to a slightly lesser extent, morality that I just don't think I have anything to bring to the table. Much of the show thrives on the light and heat that can only come from two opposing views. Whether it is Tom vs. the Abercrombie and Fitch CEO via a magazine article, Tom versus gov't bureaucracy, doo-wop and S&M all wrapped up as "Spike," Tom versus pre-teens in years 2001 to 2003, or Tom versus Maurice Kern.
I did have a well documented pro-Tommert stance
http://www.friendsoftom.com/newboard/cgi-bin/yabb/YaBB.pl?board=asktom;action=viewprofile;username=jp- I probably could have called up in support.
Now "Jamesing" as it is now known, could be an opposing view, but the problem is that the Jameses leave cowardly little weak James bombs and then run away like criminals. I'm sure if the Jameses would face Tom that it could be entertaining.
3. Some callers are legitimately funny on their own, like Petey and Paul F. Tompkins. I like those too. But I'm not going to be able to come on with my own material.
If I could listen live I'd try to call more often, but it's probably good that I don't because I'm not going to be funny (3.) and I'm not going to be interesting (2.)
That said, I'd bet if more of you could or would call it would be great. Either way I've never heard an episode I didn't enjoy.