For a new twist on a project, why not start with a tried and true color combination from a holiday, on a non-holiday related project.  Here is page that has summer pictures, with a red and green theme.  This one has quite a bit of red and green, but you could use one color predominantly, and hints of the other.  You could also vary the shades from what we normally think of as the old Christmas red and green.  Also try throwing in a third color and you really lose that holiday feel.