The first thing I thought of when I read this is Chris Traeger from Parks and Recreation, who is for being health conscious what Ron Swanson is for being libertarian. (In general, Parks and Rec has a very friendly way of being over the top, which I think is a huge part of its appeal.)
At the Australia online hangout; one of the topics we discussed (before I fell asleep on camera for a bunch of people) Was writing a rationality TV show as an outreach task. Of course there being more ways for this to go wrong than right I figured its worth mentioning the ideas and getting some comments.
The strategy is to have a set of regular characters who's rationality behaviour seems nuts. Effectively sometimes because it is; when taken out of context. Then to have one "blank" person who tries to join - "rationality house". and work things out. My aim was to have each episode straw man a rationality behaviour and then steelman it. Where by the end of the episode it saves the day; makes someone happy; achieves a goal - or some other <generic win-state>.
Here is a list of notes of characters from the hangout or potential topics to talk about.