Students have great ownership of these questions, and must really engage with the modeling process - identifying what principles apply, making and justifying assumptions and approximations, determining what information is available, etc., as well as practicing the process of asking interesting but focused and answerable questions. None of these purposes are served well by "textbook problems," not to mention that the process is more enjoyable and engaging for students when they're such a big part of it.
Here's my most recent - a video prompt that I saw while watching Phineas and Ferb with my son:
The students came up with some great questions, made measurements (including scaling) from the video, and did their analyses. It took about 35 minutes, and here are the three whiteboards from this section:
"What's the stiffness constant of the 'trampoline'"?
"What would his maximum acceleration be as he's caught?"
"What's the maximum force exerted on him by the trampoline?"
Also explored by this group, but not pictured: "From how high could he fall and not die?"
"How high does Phineas bounce?"
"How much energy was lost during the bounce?"