Those wacky theme paths

• get_template_directory()

  : Returns the absolute template directory path. (PARENT)

• get_template_directory_uri()

  : Returns the template directory URI.

• get_stylesheet_directory()

  : Returns the absolute stylesheet directory path. (CHILD)

• get_stylesheet_directory_uri()

  : Returns the stylesheet directory URI.

See also: How To Load Files Within WordPress Themes