New ideas are hard to come by.
We've done large scale pendulum demos and calculations as well as projectile motion experiments where the students get out there and toss balls around, making appropriate distance and time measurements. The facility, being so large, lends itself to a host of possible experiments, including speed of light measurements, sound and wave measurements, etc. Another idea is to take our students out on the ice surface and do momentum experiments with hockey pucks. We haven't done that one yet. So many ideas are based heavily on what people have done before.