I always get a chuckle out of the radio ads for the Duluth Trading Company, especially their spot for Ballroom Jeans (jeans designed to provide more ball room, duh) and their longtail T-shirts designed to prevent plumbers butt.
links to the radio ads can be found in the lower right of this page:
http://www.duluthtrading.com/store/dtc-shared/about-duluth-trading-company/advertisements/advertisements.aspx and their TV spots are good for a chuckle too