What to do with a smart 3 year old.

Kaitlyn loves to run in the house and shut the door and deadbolt it before you get inside. She will open it again eventually, but we try to always have our keys with us just in case. Today before dinner Richard went out to put a letter in the mail box and Kaitlyn beat him in and promptly locked the door. Richard was not happy about being locked out and got after Kaitlyn when he got back inside. Kaitlyn responded in a very serious but honest voice, "But dad, remember yesterday when we were bringing in the groceries and I did that and you laughed." Richard had to leave the room he was laughing so hard, and I just shook my head and told him, "She right." What do you do with a three year old that is so smart?! :)