I got the idea from my instructional coach; while co-planning a Data Management lesson on central tendency, she suggested that as a warm up/"minds on" activity to the lesson, the students calculate the mean, median and mode of a set of data we give them (the number of seconds various speakers at the recent Grammy Awards spoke). The twist? Rather than record their work in their notebooks, the students got to write on their desks!
Every single student was engaged, and while they worked in partners discussing their calculations, and which "average" was most representative for this particular set of data, my coach and I walked around with our clipboards and checklists to see which students were demonstrating an understanding of central tendency in their work, and which ones would appear to benefit from a little review.
Clean up was quick, too -- just a cloth and an organic cleaner spray bottle did the trick: I sprayed, while two wipers followed me around for about one minute.