Keeping track of how much time you have left to talk in a presentation or a meeting presents special difficulties. As evidence that no good solution exists for the problem, I point to the universal practice of appointing a single individual to keep track of the time who is delegated to conveys the impending end of the allotted time to the speaker. Any time a simple task is done by a human, you know it's not all that simple. But we all know that watch displays are too small, the laptop is occupied presenting slides, a one-minute alert is fine but the speaker has no way to know how close am I to the one-minute mark?
I ran across a big countdown timer at online-stopwatch.com, written in Flash. Running on a Nokia Internet Tablet, the numbers are large enough to read from ten feet away or further. It's a perfect use of the NIT's 4.3-inch screen.
Different versions of the program display a stop-watch (counting up), splits, or a circle clockface with a single hand sweeping once around the face whatever time you have entered.
You can run this useful app from the website if you want. Me, I simply downloaded the .swf file, put it into a /tools folder, opened it in tablet's browser and bookmarked that local copy. Easy to grab. And of course the graphics resize nicely as I switch between standard and full-screen display. Hey, thanks, online-stopwatch person!