Our backyard that is. We've finally started a "Rivers" unit study that I wrote a few years ago (which I have posted on a blog somewhere on the internet, but can't locate at the moment). On the schedule for tomorrow was to "build a model river", which I hadn't really worked out the details of, but was getting inspiration from this webpage. Presented with exceptionally gorgeous weather this morning, I asked the kids if they'd like to get started on it today, and I'm so glad we did. I can see this is going to be an ongoing project for them (especially since they created a watering hole for their miniature animals four years ago and still use it regularly) - a backyard river system is a natural fit for my kids. Little Brother said it's "our best homeschooling project ever", even better than ice cream in a bag.