Here is something I've been exploring, while adding new content to the website - fibonacci sequence polyrhythms like these ones: 

More videos like this in the new page: Approaching the golden ratio with the Fibonacci sequence.

What's interesting here is that, first, the golden ratio is the "most polyrhythmic" possible rhythm in a well defined sense. 

So - it is impossible for a human to play, at least without assistance, as it never repeats exactly. But ratios of Fibonacci numbers get closer and close to the golden ratio and are more accessible to a human player.

The Fibonacci sequence is 1, 1, 2, 3, 5, 8, 13, 21, ... where each number is the sum of the previous two.

Then 5 : 3 is a better approximation to the golden ratio than 3 : 2, and 8 : 5 is better still, and so on. These are also the closest possible approximations to the golden ratio.

So for humans, the 5 : 3 polyrhythm, then the 8 : 5 (if you can do it) then 13 : 8 and then 21 : 13 are polyrhythms you could try to attempt which get closer and closer to the golden ratio polyrhythm.

Though there may be other ones you can try which are also pretty close, but maybe easier to do.

You can read more about it here in the new page: Approaching the golden ratio with the Fibonacci sequence.