My husband and I have watched every single episode - usually more than once, in my case - and last night we were trying to remember if we'd ever seen Don laugh....he has genuinely smiled with Mrs. California Draper, with the department store girlfriend, etc but have we EVER seen him laugh???

I think he chuckled a tiny bit at his own joke after Roger said he wanted the Chinamen out of the building and Don replied, "But I'm still waiting on my shirts!"

And in the episode that aired earlier tonight, Joan makes a crack about how the visiting account man probably never would have expected to have been run over by a secretary on a riding lawn mower in the Sterling-Cooper offices.  Don gives a legitimate laugh.