I really like this activity too! I too feel that sometimes students just need a change of scenery or maybe it helps to get up and get their blood flowing. I had a friend recently suggest going on a "nature walk" where students can learn the difference between qualitative and quatitative data (I would do this at the beginning of the year). They can observe different things by describing their shape, color, texture, smell (qualitative), and then describe the number of them (quantitative). Also, I heard of another cool activity if and when you teach ecosystems where students could walk around outside and put together a energy web with what they observe outside.