Run script once...

[NZ_Kiwis]

I want the first user on a Sunday to run a script.... now I know how to work out if it's Sunday or not (in code as well ;-) ) however i'm wanting to know were I could save a file or something so I know it's been done??

then I could do a

if file exists then do nothing
else
run my code

Is this a good idea or no?

[NogDog]

$now = time();
$file = 'sunday_'.$date('Ymd', $now);
if(date('D', $now) == 'Sun' and !file_exists($file))
{
   touch($file);
   // run your script here
}