I wonder if it would be possible to have a dark ride with multiple, intersecting tracks and some way for the occupants of the ride vehicle to make left/right choices based on some kind of story. I could foresee all kinds of logistical problems with this but it would be a very different format if it could be done. It could be used for a simple story geared to little ones, or to a more complex story. For example, an Indy story could include as one of the choices "rescue your partner" or "follow the Ark" as choices, with the next rooms being different depending on which choice was made. Or a 101 Dalmations themed ride could include a choice to "follow. Cruella de Vil" or "chase after Lucky". The ride would have to default choose for you if you didn't. It would be novel and would have appeal for multiple rides.
As for themes, I would like to see something on 101 Dalmations.