Today was the first day my geometry students would see postulates. The book starts with the standard "through any 2 points there is exactly one line", etc. I didn't want to just present them and state their significance, so I tried something new. I handed out this True/False sheet and had the students work in their groups to determine which statements were true or false while I walked around. I heard some great discussion, and I gave them about 7-10 minutes. Not every student got every one right, so that makes me glad I did this. I'm guessing if I just presented the postulates and explained them, I'd get a bunch of nods and, "oh yes, we get it" expressions when in reality, maybe they didn't.
Here's the sheet:
By the way, 5 of them are True and the rest False (as if you didn't know :) ).