Challenge: Hellzapoppin!
Thanks to Olson and Johnson, crazy and zany is the order of the day.
Everything is going along normal. The characters are doing what they should. Dialog is fitting in with the theme. Your plot is flowing smoothly.
When suddenly.....
Your character sniffs an alien flower, ends up pregnant. Sylar prances in, passing out candy hearts and wearing baby wings. Mama Petrelli turns in to Aunt Bea and is worrying about who's stealing her pies.
The entire cast breaks out in to the fight scenes from West Side Story!
...and then things return to normal as if the interruption never happened.
Whatever makes your story a little to the side of odd, breaks the flow, is what we are looking for.