A flood of consciousness

Begin with an event and then let the thoughts carry you where they will. Have your character start a story and let the story stray off to other stories and events. Let it take off on a walk about, straying and wandering from thought to thought. This can be one way to up your word count for NaNo and also a way to allow thoughts to stream out that might spark something unexpected.

This is from #123 in Unjournaling: Daily Writing Exercises that Are NOT Personal, NOT Introspective, NOT Boring! by Dawn DiPrince and Cheryl Miller Thurston. Here's a piece of her example of Uncle Milhouse's rambling stories:

Back in 1972, you wouldn't believe the tornado that hit our town. That was the year my dad got laid off at the factory ... the pickle factory, it was. They were called Fickle Pickles, and they were the best darn pickles you ever ate. Well, maybe my grandma's were a tad better, to tell you the truth. She said her secret was to add a little cinnamon to the jars ...