Recent research has found that "high-power poses," including leaning forward, can increase a person's sense of feeling powerful. This can be used to help students work in small groups.
This is an article from The Physics Teacher Online that talks about the concept of apparent weight. Specifically, it talks about the right way, and the wrong way to teach students about apparent weight.
The Digital Wish organization has compiled a searchable, free collection of teach-submitted technology lesson plans