I have a bit of php code that includes this: $call_url = "http://www.blablabla.com?id=xxxxxxxx&show=2&subid=" . $user_subid . "&geoip=" . $user_ip; How do I rotate xxxxxxxx at a set %? For example I want it to show xxxxxxxxx 10% of the time, yyyyyyyyy 40% of the time and zzzzzzzzz 50% of the time. Any ideas? Thanks!