i have some categories that are very time dependent.

for example, 'events'.   We have about 3 events per year, but I don't want to show ones that are old.  

Any way to add a date limiter?   For example, don't show posts over X days old?

I know how to do this in SQL for some custom queries I do... but I'd LOVE to switch completely over to this plug in.
(I simply do:             AND DATE_SUB(CURDATE(),INTERVAL 30 DAY) <= p.post_date
where 30 is number of days.

Any ideas? I don't mind changing the source code of the plug in in the meantime, I'm just not sure how to add parameters?