Dewey, Cheetham & Howe is the joke name for Tom and Ray Magliozzi of NPR's Car Talk business corporation. Tom and Ray used the imaginary law firm initially as a joke, but once the show became big they incorporated the name. The brothers always refer to the firm/business name at the end of Car Talk.
Entertainment - Misc, Art - Advertising, Signs, Billboards and Writing
Links: www.cartalk.com, en.wikipedia.org