As for my son, last year his duty was to wipe the windows. Last year his class was awarded the cleanest class in the whole school for the year and he was very proud of that. Incidentally, his sisters class was the second cleanest class. They had extra presents on Children's Day for that.
When teacher was distributing duty this year, he immediately volunteered for the first duty. Something to do with rubbish, he said. The kids told me something in Chinese which I didn't understand. They both explained to me that he is supposed to be a "Rubbish Group Leader".
So what does a "Rubbish Group Leader" do? Well, the boy didn't know. He just raised his hand and volunteered and he didn't know what he was supposed to do! Eventually, we found out that he was supposed to go round making sure everyone throws their own rubbish. The kids have a plastic container where they throw their pencil shavings etc. So he needs to make sure those are cleared.
So what does he need to do if they don't throw their rubbish? Well, he has to throw it for them! However, he did not know where to throw it /where the main Rubbish Bin in the school is.
I really had a good time laughing about that. He does take his duty seriously though going round making sure everyone throws their rubbish. Perhaps he just likes to order the others around, however most of the time when I ask him he says he throws it for them. lol.