Today Caleb climbed into his crib on his own. But not to sleep. I heard him from my bedroom and went to check it out.
He spent the first few minutes jumping. Not bouncing, jumping. Man, those crib springs have bounce in them! He was flying!
Then he decided to do laps. As full speed as a 4 foot by 2 1/2 foot space will allow, he tore around and around and around the crib. Sometimes he used his hands to propel him off the end, sometimes he threw his hands out to regain balance. After a few minutes of laps he discovered that if he went really fast he could actually just careen his body of the sides of the crib and so propel himself around and around and around.
Then he was done and wanted out.