Ever played with Madlibs? They're what power the inspiration generators over at seventhsanctum.com. A madlib is basically a phrase with replacable words - adjectives, nouns or verbs (or all three) are swapped out to create phrases. Eg:

• The _______ of the _______ __________.
• The attack of the killer gooseberries
• The doom of the gargoyle mist
• The revenge of the Holy Reunion.

They can be a real laugh, especially as writing-starters. But you can take them further, to a point where your story becomes just a framework for a dozen real stories.

Write a piece of flashfiction - 100 words or so. Now see where you could swap words to make the story about something else completely, without changing the structure of the sentence or adding or removing anything. Everything has to stay the same, you're just swapping out key words.