CATS (at least used to) have one in Des Moines.
If you go to the website and get on the mailing list, you'll get their brochures ... I get two or three of each.
They may be figuring that people in some parts of the country don't have the extra money (which may, in fact, really be the problem in getting attendance for the one in the Southeast -- a good friend of mine lives in an area with a lot of retirees, and tells me there are very few jobs in town that pay more than minimum wage, and if you ask for a raise, you're told they can always get a senior citizen who'd be glad to do it for minimum wage).