Kids are playing quietly, getting along, allowing me to complete a few tasks without interruption. It's the exact scenerio I strive for as a parent but there is a downside. If they've been that good it's because they've been working so hard on some extensive Lego set-up or art display that takes up half a room. With my kids you can bet it's probably in the middle of a walkway or smack in front of the back door. Considering their angelic behavior of the past hour I try to show some empathy when it comes time to clean up "the mess". Don't you hate it when you spend 20 minutes folding laundry and someone knocks over the laundry basket? I imagine they feel the same about wrecking their creations.
If they are having a hard time letting go, whip out the camera! The kids know that their work/effort is valued and they love getting to play photographer for a couple of minutes.
This has really helped at our house. As a parent, I expect my kids to do what I ask of them. It's much more peaceful when they do what I ask and have a good attitude about it.