Since Meredith is crawling a couple of months earlier than Mackenzie, I'm already having to tell her no when she tries to mess with things on the floor. Her two favorite items to go after are the floor antenna in the living room (we don't have cable) and the laptop battery charger. I've also pulled the playroom blinds up a little so that she can't reach them. When I pick her up I shake my head and say no, but now she thinks it's a game because she can do it too! I'm sure it doesn't help that I've tried to take a video of her shaking her head.
Even though we are trying to teach her something, we can't help but laugh when she shakes her head at us.