Her "Freaks and Geeks" co-stars may have gone onto greater fame and success, but we've always had a soft spot for Linda Cardellini, who starred as rebellious teen Lindsay Weir on NBC's one-season wonder. We were thrilled, then, to see Cardellini last season as Don's latest mistress, married neighbor Sylvia Rosen. Don and Sylvia's tryst is over, but we still hope we get to see more of Cardellini this season.
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