The American Folklife Center    Voices from the Days of Slavery, Motion Pictures in American Memory, Television Reading Room, Sound Recordings give immediacy to our history.
                                             The Veterans Project gives you tips on interviewing veterans to preserve the stories of local veterans.  You can send these to the site for preservation.
                                            The site is dedicated to the documentation of American culture "from folk songs recorded in the early 1920w to ...the evolving symbolism of yellow ribbons.
                                           " Lesson plans K-12 ...that promote student inquiry and develop critical thinking skills."  Primary sources and their use are stressed.

Elections...The American Way  Questions about who and what are candidates, voters, issues, process, and the party system are investigated.  Many other features and activities involving various                                                 periods of our history are addressed with excellent, creative ideas and plans for teachers.

The New York Times Learning Network  I looked at this site especially for Current Events but found it has something for everyone. Go to the bottom of the home page and pick your subject. Math                                                          department take note!  It's harder for me to find sites relevant to your topic, but this looks good to me for why math is important in everyday life.