Hoping to draw on the vast expertise of the WinCustomise userbase   ...

I'm looking for a task scheduler to run under WinXp or later that you can setup exceptions to the rule. To clarify:

I want to setup task(s) that run every Mon-Fri at certain times - this is easy and can be done in one line of crontab or windows scheduler, but for my needs there are certain days or more correctly dates (eg public/school holidays) on which these tasks musn't run.

To my mind it would be much more convenient to schedule the exceptions which occur on proportionally fewer days than the main tasks which should otherwise occur every day as appropriate.

If needed I'm prepared to do it the hard way & generate (say) a crontab file that specifies onyl the dates on which the tasks should run, but even here, so far, I haven't found such a task scheduler that supports individual dates. The apps that do support dates all seem to be PIM/Calendar types that don't do task launching very well (if at all).

I'd rather not have to write something from scratch if at all possible, so all suggestions welcome. TIA.