Visible timer in OpenOffice presnetation?

[STUMPOFWAR]

I am a teacher......I use openoffice for my classroom presentations.

I like to do timed activities (warmups, readings, etc etc)

Is there a way to get a timer to be viewable on the slide so that the students can see how much time they have......without me having to take down the slide with the directions.

I've done a quick few searches in google and at openoffice's website....but all of the hits were for the timing between slides and not an actual timer itself....

Thanks,

Shawn

[samden]

If you save the presentation as a .pdf and use Impressive to present it, you can get a visible timer plus all the other useful extras Impressive gives.
http://impressive.sourceforge.net/

But there should be a native solution too I would have thought.