HTML block that can be closed/minimised?

I'm considering adding a small HTML/PHP block above the main wall on our members pages that can be closed or minimised after it has been read. Perhaps this could be used for site updates, or urgent notices, or in our case a note about how to control privacy on the site. Otherwise this is on a separate page so it is not annoying on the wall page all the time. Any thoughts?

This could probably be done if you created a design box that included this, then set the block item in question to use the design box (this would need to be done via the database).

I wouldn't have the first clue about creating a design box with a close button, or minimise button

I guess a collapsable panel could be done using CSS, but I've still not managed to achieve an HTML block without borders and a title yet.

I used to have a mod for D6 called admin announcements that disappeared after the member clicked that they read it. I have not done a D7 version yet as there does not seem to be a demand for it.

I still may bring it back at some point.

That sounds ideal Deano...!

As a follow-up to this post from June 2010, here's Deano's "Admin Announcement" module for Dolphin 7.x:

Admin Announcements :: deano92964's posts