Clang Bang Rattle!

Ok, this is strange! I am not sure if everyone is aware of the typ of people I live next to. (I am in a fourplex) How they don't like us to talk after 9 and if we do they bang on the walls or call the cops and also call the owner so we get a talking to about talking.
Anyway..so I wake up this morning and sara is feeding Robert in the kitchen, I am at my computer with the morning coffee to get me started and then I hear some banging..really fast banging. The cat comes running into the livingroom. I had thought Sara was doing it to scare the cat away. She walks into the living room and goes..what was that?! They were pounding on the wall! I don't know why..but I know they were because next thing they were pounding on the livingroom wall and then up the stairs. It stops for a minute.
I am standing in the kitchen now talking to Sara wondering what is going on because we are not making any noise. The wall starts pounding again! Pounding so hard my picture (a big wooden one) was jumping and I really though it might fall.
This is just crazy! There is no rerason for that at all. For all they knew one of us could have been sleeping. So When the landlord comes tonight to get the rent I will mention it to him. Not like anything will be done about it (Oh more pounding??? WTF?!) Anyway...not like he will do anything about it even though we are the only ones that pay rent everytime on time.
Some peoples Kids!! (and no it is not the kids doing the pounding!)