My year 7s have recently taken a Christmas break from a creative writing project. Much like the Choose Your Own Adventure, we ended each lesson on the students picking on of two cliffhangers, and rolling a dice to decide which would form the basis of the next story.
In terms of differentiation, some students were given the option of something happening, or not happening. They would build up to the event (falling down a hole was popular, especially given that it was snowing at the time) prior to rolling the dice. For them, interestingly, they were particularly excited if the event happened.
A digital dice:
http://www.random.org/dice/
or an analogue dice:
http://bighugelabs.com/flickr/cube.php
