You could be forgiven for forgetting what on earth has happened up to this point on the series Mad Men, which comes back Sunday night with a two hour episode kicking off season five. After all, it has been eighteen months since the last new episode aired. Thankfully, the internet comes through in pop culture emergencies such as this, so you can choose from (at least) two different ways of jogging your memory:
Jezebel runs through the show's history character by major character, which was helpful since I would have been very confused by any future references to Abe Drexler.
New York Magazine goes through each episode in condensed form, giving more extended treatment to the show's ten best episodes.
Or, just read both and regale your friends with your exceptional mastery of the show's backstory. Assuming your friends spend quite a bit of time talking about Mad Men. If that's not the case, perhaps there are better uses of your time.