Ideas for Writing: Five plot-centered prompts to get started!

Be kind, please. I've never actually done something like this before. Well, OK, that's not 100% accurate. Once in a grad class, a professor asked us each to create our own writing prompts. Then he read them (anonymously, thank goodness) out loud and we all picked one for a free writing exercise. He didn't withhold his opinions, however, on which prompts were worthy and which ones were crappy. I remember when he read mine, he raised his eyebrows and blinked three times in row, a facial expression that could only be construed as: Whoa, this one's out there. I still believe very much in my prompt! In fact, I included it below--see if you can figure out which one received the 'look.'

Anyhow, these are some original writing prompt ideas. In this segment, they relate to the plot points of a novel, story, poem, etc. If you've seen any of them before, it's pure coincidence. As far as I'm concerned, they all come from my intrinsic writing brain:

1. A woman is standing at her kitchen sink washing dishes, when she notices, from out the window, a solitary, red (or any color, really) balloon floating in the vast sky. This reminds her of a significant childhood experience. Write about it.  OR A solitary, red balloon is floating in the vast sky. Tell the story of how it got there.

2. Four teenage friends are trying to get into (any concert) back in (any year). Write about their adventure.
For example, it's 1978, and four high school sophomores from New Jersey are just dying to get access into CBGB's. How does the night unravel? This may or may not require some research.

3. An old man from the World War II era is taking a long train ride to visit his grandson. When a  strange woman takes a seat across the aisle from him, he is suddenly taken by a distant memory--the day he lost his virginity to a prostitute while in the service. This also may require research.

4. A little boy (or girl) gets separated from his mother at a carnival, and witnesses something that terrifies him. Tell the story from the child's point-of-view.

5.  A young man sees a young woman in a movie theater, and swears he knows her from someplace. He barely watches the film, because he is trying in vain to figure out why she seems so familiar. After the credits, he follows her outside and approaches her. Who is she? What happens?

This is a fun exercise because it not only gives my readers potential ideas, but it gives me ideas too. Any of these prompts can twist and turn in directions a writer never expected. That's really the beauty of it all, isn't it?

Anyone else want to contribute? Pen your own writing prompt below!