Just my 2 cents… I would not make it part of school and I would not make them do it if they weren’t enthusiastic about it. Because this is prayer we are talking about, I wouldn’t want to do anything to make that negative for the kids. There is plenty that I require of them whether they like it or not, but this would not be one of those things. I want prayer to be a joy, not a chore. One thing I have frequently thought about doing, but never have, is to put up a nice bulletin board or some such near the dining table with a stack of notepaper nearby so that anyone could put stuff up on the board. This would also serve as a great reminder at prayer time. Additionally, it would be a great place to put thank you’s for answered prayers.