Random stories FROM Jim, like he gives at cons...like about his sensei, or the pokemon dare that lead to the Fury books, or a conversation between him & Shannon about Shannon's car asking her to buy things....
Actually, some Shannon input on her book may be good around publication time. I know it's a JIM podcast, but...
A question and answer thing may be good, too, where you ask people to send in questions, Jim answers them. (Or answers questions for the boards. I'm assuming the whole audience of the podcasts will not consist of people from the boards.)