Does WP, php, or a current framework (woofoo / genesis, etc). Offer a way to schedule text / bg color changes?

You could just create different style sheets for each color profile, and load those depending on which month it is. Here’s a basic example showing how you could load a halloween.css file for october, and an xmas.css file for december. The code below would go in your themes functions.php file:

add_action('wp_enqueue_scripts', 'seasonalCSS');
function seasonalCSS()
{
    // register stylesheets to be loaded safely
    wp_register_style('halloween', get_stylesheet_directory_uri() . "/halloween.css");
    wp_register_style('xmas', get_stylesheet_directory_uri() . "/xmas.css");

    switch(date('n'))
    {
        case 10: // if it is october...
            wp_enqueue_style('halloween'); // load halloween.css
            break;

        case 12: // if it is december...
            wp_enqueue_style('xmas'); // load xmas.css 
            break;
    }
}