String Theory:

For a general introduction to the subject, look at  The String Theory Landscape, an introductory article from Scientific American.
 
Additional information can be found in the following links, in order of decreasing amount of information, but increasing fun:

The Official String Theory Web Site
,  a comprehensive site of information for non-scientists with an interest in superstring theory.

A conversation with Brian Greene
, a PBS interview with the author of The Elegant Universe, a popular book on string theory. Also check out the link to their Nova TV series"The Elegant Universe".

A Great Unraveling
, a New York Times Book Review on two recent books doubting the usefulness of string theory.



Here are some questions to think about:
    1) String theory has been around now for 20 years.  Is it useful and do we need it?
    2) What are superstrings?
    3) How many dimensions does our world have?
    4) Is there a difference between a coffee cup and a doughnut?
    5) What next?