As I have eluded to here and here, I knew it was a matter of time.
This morning Elliot called out for Daddy to come get him. Fred walks into his room and opens his window shade. Turns around and Elliot is straddling his crib. He says "out now?" Two seconds later he is hanging off the rail and one more second he's on the ground standing.
Looks up at Fred and says "eat now?" and walks out of his room.