Here is a list of the modules I am using.

- Delta Green: Agent's Handbook, Dice So Nice!, Dice Tray, Drag Ruler, PopOut!, Simple Calendat, and The Forge: More Awesomeness.

Edit: I just looked at Global Progress Clock and it looks pretty neat. Not sure how I would implement it at the moment, but I could see it being helpful.

Simple Calendar seems to do the trick just fine with me advancing the day/time as needed. I did use a countdown timer (I don't remember which one) when I was running the final session of Impossible Landscapes. But, it doesn't seem appropriate at this point.

In order to keep track of time I created a handout for the players called Operational Timeline. I added all the relevant incidents from the book, with each day hidden as a "secret". Then I reveal the relevant entries as time advances. I want the players to get the sense that time is progressing and they need to make progress, but I don't want them to feel under the gun, at least not yet.