depending on your cirty you can definetely get a passport that same day. i didnt realize that my passport was expiring in a month after my trip to london, amsterdam, paris and brussels.

I called the 800 number for the US passport office and they tld me that every country was different but that as a rule, airlines should not allow you to board if it expires in less than 3 months.

go to google and type, "united states passport office." go to their official website and see if there is an office in your city. if there is, you will have to make an apnt on an automated system. if you actually get and appnt you will be able to get the passport that day. its an additional $60 and be prepared to wait all day. you will need proof that you are traveling with in the next 1 days. in my case it was the next two days. you will also need to bring a passport photo.