The Word-at a-Time Story improv game is a great warm up exercise, class exercise or theatre sport game for any ground of improvisers. The trick, as with all improv, is listening.
Stand your group in a line, semi-circle or full circle.
Step2
Have one person start the one word story with an active verb, such as "Running."
Step3
Going in order, have each improviser contribute a word until a whole sentence has formed. The words should not be thought hard about, but rather the first thing that comes into one's head.
Step4
At the end of the sentence, the next improviser can say "period" or "question mark" etc, as her turn.
Step5
Continue to tell the story as long as you wish. Five minutes will probably be plenty of time.
Tips & Warnings
The trick is not to try and be funny, but rather to make the story make sense.