To generate a random number which is different every day, I used the number of days after unix epoch as a seed:
<?php
srand(floor(time() / (60*60*24)));
echo rand() % 100;
?>
My provider upgraded the php server recently, and calling srand(seed) does not seem to set the seed anymore. To let srand set the seed, add the following line to your .htaccess file
php_value suhosin.srand.ignore 0
Kudos to doc_z (http://www.webmasterworld.com/php/3777515.htm)
Harmen