Before she sold us car insurance as Flo the Progressive Lady, Stephanie Courtney answered phones for Sterling Cooper as switchboard operator Marge back in Season 1. She's always all about the customer service, though.
The halls of Sterling Cooper & Partners have been filled with a lot of familiar faces lately. Here are more than 20 "Mad Men" guest stars we recognize from previous roles in TV and movies. — Dave Nemetz, Yahoo! TV