EJ got up on her hands and knees yesterday and started rocking.  When I put her down she's no longer in that same place when I come back.  She's not crawling yet, but she's scooting around on the floor and rolling until she finds herself someplace interesting.  She can sit up by herself now.  She'll still fall over, but she doesn't seem to mind when she does, because that gives her a chance to scoot and roll.  

Time to baby proof.