Have you ever had multiple students get excited before, during, and after a final, and then tell you it was the best final they'd ever taken? Granted, we're talking about a creative writing class that didn't technically need to have a final, so I'm not saying this assignment will fit as a final for your class, but it can be that 90-minute timed assignment to take care of a creative writing unit. All three timed assignments last around 90 minutes.
Be prepared to be amazed when students who have barely written anything all semester suddenly have a four-page short story to turn in. In fact, if you are teaching a short story writing unit at the high school level, ditch it for this (unless you've found a way to create magic already). It's basically three templates for tight little short stories. You could spend some time editing them, and you'd end up with better short stories much faster than the traditional means.
Did I mention that these scenarios are fun? You'll find yourself imagining along with the kids, maybe even writing along. Want an inservice idea that doesn't suck?
Keep in mind that I only taught this particular choose your own adventure type of writing assignment as a final, so I'd had time to establish my personality, and the students knew each other fairly well, which helps in one of the scenarios. Using them a couple of weeks into the semester should work just fine. Translate and use in a World Languages class. Use in an art class and have students create illustrations for each part.
Do you realize that a lot of employers think students lack creativity when they graduate from high school? Do you think another test and another data point is going to help? Here's your chance to see student creativity unleashed in 2 class periods. If you lament the loss of your school's poetry unit or wish you could teach just a little bit of creative writing but had no clue how to fit it in, this is a perfect little lesson for you.
Make sure you try all three. Two of the scenarios were written for seniors and one was written for 9th graders. Easy to alter, but I gave more guidance to the younger students. Therefore, some of the instructions might appear vague. Don't worry. Just use it and encourage the students to figure it all out for themselves, which is the point.