Translation:You are the donkeys, we are the horses.
I still think it is utterly pointless to design ridiculous phrases like this, when more natural phrases can serve exactly the same purpose! For this example, change the words sunteți and suntem for aveți and avem and, all of a sudden, you have a perfectly sensible sentence that still teaches exactly the same structure of the definitive plural.
Okey... the person speaking this sentence is talking about two Soccer teams - Magarii si Caii
So, those of you complaining about artificial sentences that don't make sense, maybe you just didn't spend enough time coming up with a scenario. Just like that sentence about George's clothes betraying him, it's possible to come up with a scenario.
I keep wondering though about the one about a guy whose ankle is full of mustard. I haven't came up with a scenario for that yet.