Thermometer for PowerPoint (current version: 1.1) is a free add-in that creates a thermometer style bar in the bottom area of the slide that shows how much of a presentation has progressed and how much more is remaining.

But then what might purpose can this be off..?..well havent you felt the urge to get out of certain presentations..just because how much more the speaker has to say..!..well its exactly for that kinda situations..just a goodwill jesture to the audience..incase they really need to know how much more you would take to finish ;-).Get it here.
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