4th and 7th period physics experimented with waves on slinkys in the hall. This group is working to figure out how they can increase the velocity of the wave on their slinky. It took them a while and even then, they needed a huge hint from me. Once they saw it, the kids were kinda wowed by the dramatically faster wave they created.
Oh, and lab groupings came from the first day activity, Subversive Lab Groups.