A guy I knew a few years ago could ride a unicycle whilst juggling 6 oranges . He said it was easy - although he admitted he had been riding unicyles for many years from when he was a teenager.
I tried it in 2 stages - first of all trying to ride a unicycle - that was very difficult and although I did manage to stay on a few times - I could not even juggle 2 oranges at the same time - even though I could juggle 4 or more when I was just focusing and concentrating on just that part and not try