Physcis Extension Unit Ideas - Please Help

I am a gifted education teacher. Part of my job is to pull kids (the top 15%) out of their core classes for a unit and push them at a higher level. I will be working with 8th grade science and have to cover the following learning targets.

1. I can explain how acceleration is related to velocity.
2. I can calculate acceleration.
3. I can interpret distance, velocity and acceleration from a variety of graphs.
4. I can graph distance, velocity and acceleration.

I am in need of some project ideas. I need something that is challenging and at the same time something fun and engaging for these kids.

I have one idea that I am toying with, but not sure how to mold into the learning targets above.

Here is the idea that I am working on right now

They bring in a shoe box and make a marble drop for 30 seconds. They have to figure out how to slow the marble with either materials(ramps) It has to drop the entire time. That forces students to think about gravity, speeds, friction. Maybe something like this sort of idea.

Please help out with any other ideas or thoughts. I am having a brain fart and cannot get going on an idea.