The county I work for, has a math department that provides tons of professional development. This idea came from them. I just added a few things here and there to make it fit my style.
Organizing data using a three set Venn diagram is an easy task since I learned this new trick :)
I used:
3 Venn diagrams, 3 copies of the Woozles (different colors) and tons of modeling.
We made a chart with possible attributes to sort our data (Woozles).
I modeled how to choose three attributes. We used laminated Wozzle cards and the kids came up to the whiteboard (I really want a smartboard!!!) to tape them. They were sure to check that each Wozzle was placed in the correct spot.
Then kids worked in teams of 4-5 members. Each team had a pile of Woozles to work with. They decided what attributes to use for their poster and got busy taking turns/voting for the attributes they wanted, choosing who was cutting them, choosing who was gluing...
We created statements that described our data. The kids created statements for their posters too.
Oh Yes! Math is my thing.