Now that Ethan is walking quite confidently we have started playing Hide and Seek.  It is so much fun and he finds it absolutely hilarious!    I run ahead of him and hide behind a door or behind the couch and he follows and finds me and bursts out laughing and gives me a big hug.  It's lots of fun, a great way to tire him out and good for him to understand that even if he can't see me, I'm still there (object permanence) which is good for him when we are separated, a part of his Personal, Social and Emotional Development.