We have been using Storyathon.com to have a go at writing microstories. These are stories that are exactly 100 words long- not a word more, or a word less.
WE also use the One Hundred Word Challenge, 100wc.net, to also write microstories, although their word count criteria is a little bit more flexible.
Microstories force the writer to think long and hard about which words they actually need. It is challengung to open with a hook and finish with a plot twist, in just 100 words.
Here are a few of our examples. The prompt was "IT wasn't me" ...