color-rotator.php

<?php
/*
Plugin Name: Color Rotator 
Description: Change the color scheme every time you login 
Author: Aaron Jorbin
Version: 1.0
Author URI: http://aaron.jorb.in/
License: GPLv2 or later
*/

// Every time a user logs in, change the color scheme
add_action( 'wp_login', 'jorbin_color_rotate' );

function jorbin_color_rotate() {
    $new_colors = array( 'fresh', 'light', 'blue', 'midnight', 'sunrise', 'ocean', 'coffee' );
        
    $color_scheme = array_rand( $new_colors, 1 ); 

    update_user_meta( get_current_user_id(), 'admin_color', $color_scheme );

}

Forking so you can do it with no hook? 😄

I was originally just going to fix your spacing, but then ... I just couldn't do ectoplasm something something crossing streams slimer.