My dear HH wakes up bright and early to walk - get some exercise before heading to the office - while I'm still sleeping. Boo sometimes wakes up during this walk, so he will leave a note on the floor by the front door: "Daddy walk. Back 7:30. I love you." Now that Boo can read, he gets a particular delight out of being left a note. By daddy.
Tonight, when my husband came home from work, late after two evening meetings, he found this by the door: