Make product unavailable on certain date

Is there a way to make a product unavailable or turn it off by date/time? I need to stop online sales of event tickets a day or two before the event, because I don't have a way to process them in the office. Ideally, the product would still be visible, but with a call for price or buy at box office button instead of an add to cart button.

I've searched, but can't find anything on this. I'm a newbie, so detailed instructions are appreciated.
-Running v. 1.5.1 and Sheffield Blue template.-

Okay, I finally figured out to search for some version of the word "expire" (my brain finally turned on), and found the mod in this thread:
http://www.zen-cart.com/showthread.php?95237-Setting-products-to-expire-at-certain-date/page2&p=793533

How can I tell if anyone has got this to work? Or is there somewhere I can go to get hand-holding? I'm setting this up for a non-profit, and we can't afford help or even the book right now.

I saw other posts about using featured products, but I can't get that to take it down, it just changes the price. Is there some way to use it so products (tickets) can't be sold after a certain date?

I'm plodding through information as much as my schedule will allow, but any help (or pointers in the right direction) would be appreciated. I know I can do this manually, but I won't be around for them forever.