I have the sheets printed out and in a folder all ready to go a few weeks ahead of time. I have found a lot of great questions on Make Learning Fun (if you have not checked out this website, I love it! Lots of great ideas on lots of topics). There is section called Question of the Day. The questions cover all types of content and I often am able to find one that fits in with our current theme.
I have received a lot of positive feed back from our question of the week as it allows others to get to know my students more and allows my students to become more comfortable talking to various people in the school building.