Engineering Class Suggestions

I'm part of an Engineering Club at my school and we're looking for future projects that just explore some ideas of Engineering in general. We would like to come up with our own ideas at some point, but for now, a lot of us are inexperienced, so I thought I could come here and find some stuff.
So far, we have decided to build a bunch of Stirling Engines and use them for miscellaneous things, but after that, we have no other ideas.
Could you guys come up with some ideas (possibly your own or ones that you have done), that are similar to this idea of teaching the basics of making things and stuff like that? Links would be helpful.

Guidelines:
Because we do this at school, there are certain rules that prevent us from bringing large knives and laser pointers on campus. Power tools and exacto knives are OK, though (IKR?). Also, because we are students, we have to scavenge around for materials, so unless it's less than ~30$, we might not be able to do that either.

jaxter184 (author) 5 years ago
So far the ideas are good, but...
-I'm not sure about pinewood derby because there aren't many hills nearby.
Most of us did the thing with paper towers in physics class earlier this year,
-The stirlings will be used to make small cars and USB chargers. I forgot what else, but we came up with a bunch of ideas.
-The exoskeleton sounds expensive, could you give me a link to an instructable (if there is one)?
Tim S.5 years ago
Well, you could have a pinewood derby...

Or, if you want to learn some electronics, you could buy Arduinos and fiddle with those... get some LEDs and setup some blinkenlights....
Kiteman5 years ago
How about...

Give everybody the same sized sheet of (plywood? card?) with the intent of building the tallest possible structure from that sheet and nothing else (no glue, tape etc, just slots and careful balancing).

What things will you use your stirlings for? Have you thought about vehicles or boats, then racing them? Or adding remote or autonomous controls (have you seen the steam-powered R2D2?)?

Try for an exo-skeleton suit that can carry its own powersource, plus an extra load?