Sometimes, we spend so long working on a problem or a challenge that there is little time at the end of the period to encapsulate all the little "a-ha" moments students have had throughout a learning activity. The nice thing about having such a large IWB in my classroom is that I can show multiple solutions or approaches to a problem, and still have space left to record general observations from the collective.
Today we represented 3-digit numbers in as many ways as we could. Some students used multiple base-ten block representations, while others used money to show the number. A few also came up with some interesting analogies.
At the end of the lesson, after we had shared some students' solutions, I took a moment to record "What we learned" on the right hand side of the board, to summarize the learning. I left the board up during lunch, so that students could reflect on and continue to discuss with peers their learning as they ate. :-)