In at least one prominent case, the answer seems to be Waco, Texas. Here's the individual in question, Congressman Joe Barton, grilling Energy Secretary Steven Chu (you remember, the Nobel Prize-winning physicist) on "where oil comes from":
The remarkable thing is that this ambulatory sack-of-hammers was actually delighted with his performance, subsequently twittering supporters:
I seemed to have baffled the Energy Sec with basic question - Where does oil come from? Check out the video: http://bit.ly/O4m0p #tcot
And yes, Barton is the ranking minority member on the Energy & Commerce committee.