Sorry, but I think you and many of the others here need to go back and read his question. He didn't say he wanted ideas for labs, he said he wanted his students to contribute to real science, as in, do things that lead to publications by professional physicists.
While I did many of the experiments that you did and found them interesting and learned a lot from them, none of those produced publishable results.
You made fun of Galaxy Zoo, but the work that the thousands of people did who participated in that experiment led to real publications in the astronomical literature.
Astronomy in particular is a science where amateurs can contribute and I think he cited Galaxy Zoo not because he thought it was better than building a Foucault Pendulum, but because it has a different goal -- it is getting his students to put in their time as essentially free labor on science projects much larger than they could do in class. Although, maybe you know of a high school building a 3.5 meter telescope with a drift scan camera and multi-object spectrograph that is recording images and spectra for a million galaxies. Because at that school, kids could get the same experience the ones in his class got by participating in Galaxy Zoo.