Another wonderful tool I have been able to use recently was the Vernier Motion Sensor.
Our 6th grade science course has a Motion and Forces Unit, and this motion detector and its software has been a great teaching resource. Students connect the sensor device to a laptop and then aim it at their partner. The partner then physically models states of motion such as: forward, back, back 'n forth and motionless. The sensor picks up this information (using echolocation, similar to a bat) and records and displays this on a laptop screen using logger lite software.
In real-time the screen displays a distance-time graph, and the kids are able to make connections between how they have just moved, and the shape of the resulting graph. Experimentation can occur, with creative movement giving interesting looking results. The reversal of this idea can be used as a teaching point, with students given a graph, and then they have to move a certain way in order to mimic the graph. To be successful with this means that kids have to really understand the nature of a distance-time graph.