More Time Outside

I run a small day care out of my home.  I watch four children besides my own and I am always looking for fun outdoor games to help keep them entertained.  We spend at least an hour a day on outdoor activities and two hours a day on learning activities.  The rest of the time they read or play imaginative games inside.  I have been thinking of increasing the time they spend outside on nice days now that most of the kids are a little bit older.  They seem to have so much energy and sometimes without enough outdoor activity they do not play as well inside or concentrate on the learning activities.