Robot Design and building activity

So I want to train my team on building something using CAD and then protyping this thing with like plywood and stuff. There will be 2 meetings. the first will be designing it and the next will be constructing it using band saws, drill press, etc.

Does anyone have any good project ideas? (It has to be human powered so no motors. Some of the ideas I was thinking was a catapult to launch the 2014 ball, building something to put a ball into a bucket on a table and you could only move levers and stuff from below 24", or also using a human pushable chassis (so with caster wheels) and have students make a device to pick up ping pong balls and put them into a container (still no electronics)

I would go with the catapult idea. Our team made a tiny t-shirt cannon out of FTC tetrix pieces. We all had to build differnt robots and the mentors judged them. If you don’t use electronics then a catapult would work very well.
I would split your team up into a couple groups and the groups compete against each other. A little competition always makes it more fun!